From 384a206737c88ce79da0c0edb02e49ebe2ae2b9a Mon Sep 17 00:00:00 2001
From: can1357 <me@can.ac>
Date: Tue, 2 Jun 2026 06:50:03 +0200
Subject: [PATCH] refactor(task): replaced numeric-prefix ids with name-first
 agent output ids

- Changed `AgentOutputManager` to use requested names verbatim, adding `-2`/`-3` suffixes only on repeats (e.g. `Anna`, `Anna-2`).
- Renamed main agent id from `0-Main` to `Main`; nested ids now use dot notation without numeric prefix (e.g. `Parent.Child`).
- Updated task widget to render dotted hierarchy as `Parent>Child` breadcrumb without leading index.
- Resume scan now tracks seen names instead of a counter to avoid clobbering prior outputs.
---
 docs/blob-artifact-architecture.md            |  2 +-
 docs/tools/eval.md                            | 10 +--
 docs/tools/irc.md                             |  4 +-
 docs/tools/task.md                            |  2 +-
 packages/coding-agent/CHANGELOG.md            |  1 +
 .../coding-agent/src/async/job-manager.ts     |  6 +-
 .../coding-agent/src/prompts/tools/irc.md     | 12 +--
 .../coding-agent/src/prompts/tools/task.md    |  2 +-
 .../src/registry/agent-registry.ts            |  2 +-
 packages/coding-agent/src/sdk.ts              |  4 +-
 .../coding-agent/src/session/agent-session.ts |  2 +-
 .../coding-agent/src/task/output-manager.ts   | 88 +++++++++----------
 packages/coding-agent/src/task/render.ts      | 11 +--
 packages/coding-agent/src/tools/index.ts      |  2 +-
 .../test/task/output-manager.test.ts          | 64 ++++++++++++++
 .../test/task/render-nested-live.test.ts      | 28 +++---
 16 files changed, 146 insertions(+), 94 deletions(-)
 create mode 100644 packages/coding-agent/test/task/output-manager.test.ts

diff --git a/docs/blob-artifact-architecture.md b/docs/blob-artifact-architecture.md
index 7a3f2a19a..9233f3b90 100644
--- a/docs/blob-artifact-architecture.md
+++ b/docs/blob-artifact-architecture.md
@@ -76,7 +76,7 @@ Non-persistent sessions without an adopted manager can store `saveArtifact(...)`
 
 ### Agent output IDs (`agent://`)
 
-`AgentOutputManager` allocates IDs for subagent outputs as `<index>-<requestedId>` (optionally nested under parent prefix, e.g. `0-Parent.1-Child`). It scans existing `.md` files on initialization to continue from the next index on resume.
+`AgentOutputManager` allocates IDs for subagent outputs from the requested name, used verbatim the first time and suffixed (`-2`, `-3`, …) only when the same name repeats (e.g. `Anna`, `Anna-2`). Nested outputs are grouped under the parent prefix (e.g. `Parent.Child`). It scans existing `.md` files on initialization so a resumed session never reuses a name that would clobber a prior output.
 
 ## Persistence dataflow
 
diff --git a/docs/tools/eval.md b/docs/tools/eval.md
index 442c6e46c..835730249 100644
--- a/docs/tools/eval.md
+++ b/docs/tools/eval.md
@@ -132,15 +132,15 @@ Implemented in `packages/coding-agent/src/eval/js/worker-core.ts`, `packages/cod
   - `read`, `write`, `append`, `sort`, `uniq`, `counter`, `diff`, `tree`, `env`, `output`
   - `tool.<name>(args)` proxy for arbitrary session tool calls
   - `llm(prompt, opts?)` for oneshot, stateless LLM calls (see _Oneshot LLM helper_ below)
-  - `agent(prompt, opts?)` for a single subagent call, plus JS-only `parallel()` / `pipeline()` bounded-pool helpers (see _Subagent helper_ below)
+  - `agent(prompt, opts?)` for a single subagent call, plus `parallel()` / `pipeline()` bounded-pool helpers (see _Subagent helper_ below)
 - JS helpers that touch the host/runtime boundary are async and `await`able; pure text helpers (`sort`, `uniq`, `counter`) return synchronously but may still be safely awaited.
 - JS helper signatures use a trailing options object rather than Python keyword arguments:
   - `await read(path, { offset?, limit? })`
   - `await tree(path = ".", { maxDepth?, hidden? })`
   - `sort(text, { reverse?, unique? })`, `uniq(text, { count? })`, `counter(items, { limit?, reverse? })`
   - `await agent(prompt, { agentType?, model?, context?, label?, schema? })`
-  - `await parallel([() => agent("a"), () => agent("b")], { concurrency? })`
-  - `await pipeline(items, stage1, stage2, { concurrency? })`
+  - `await parallel([() => agent("a"), () => agent("b")])`
+  - `await pipeline(items, stage1, stage2)`
 - `display(value)` behavior:
   - plain objects/arrays become JSON outputs
   - `{ type: "image", data, mimeType }` becomes an image output
@@ -199,7 +199,7 @@ Both runtimes expose `agent()` — a single subagent invocation routed through `
 - `context` supplies shared background; `label` controls the `agent://<id>` output label prefix.
 - `schema` passes a JSON Schema to the subagent structured-output path. When present, the helper parses the final JSON text and returns an object.
 - Spawn restrictions use `session.getSessionSpawns()` exactly like the `task` tool. Eval-driven subagent recursion is capped at depth 3.
-- JS also exposes `parallel(thunks, { concurrency })` and `pipeline(items, ...stages, { concurrency })`; both use a bounded async pool with default concurrency 4, max 16, preserve item order, and propagate rejections.
+- JS and Python both expose `parallel(thunks)` and `pipeline(items, ...stages)`; both use a bounded async/threaded pool whose width tracks the `task.maxConcurrency` setting (the same ceiling the `task` tool uses; `0` = run every item at once), preserve item order, and propagate rejections. The width is fetched live from the host via the `__concurrency__` bridge, so the helpers no longer take a `concurrency` argument.
 - Errors surface as exceptions: unknown or disabled agent, disallowed spawn, recursion cap, subagent failure, or invalid structured output all fail the eval cell.
 
 ### Multi-language call behavior
@@ -245,7 +245,7 @@ A single tool call can mix Python and JS cells. Persistence is per language runt
 - Output truncation window: 50KB default (`DEFAULT_MAX_BYTES` in `packages/coding-agent/src/session/streaming-output.ts`)
 - Output line cap inside truncation helpers: 3000 lines (`DEFAULT_MAX_LINES` in `packages/coding-agent/src/session/streaming-output.ts`)
 - Streaming tail buffer for live updates: `DEFAULT_MAX_BYTES * 2` = 100KB (`packages/coding-agent/src/tools/eval.ts`)
-- JS `parallel()` / `pipeline()` helper concurrency default: 4; maximum: 16
+- JS/Python `parallel()` / `pipeline()` helper pool width: the `task.maxConcurrency` setting (default 32; `0` = unbounded), resolved live via the `__concurrency__` bridge (`packages/coding-agent/src/eval/concurrency-bridge.ts`)
 - Eval-driven `agent()` recursion cap: task depth 3 (`EVAL_AGENT_MAX_DEPTH`)
 - Python retained kernel idle timeout: 5 minutes (`IDLE_TIMEOUT_MS` in `packages/coding-agent/src/eval/py/executor.ts`)
 - Python retained kernel cap: 4 sessions (`MAX_KERNEL_SESSIONS` in `packages/coding-agent/src/eval/py/executor.ts`)
diff --git a/docs/tools/irc.md b/docs/tools/irc.md
index 98996443b..bf2ff70a3 100644
--- a/docs/tools/irc.md
+++ b/docs/tools/irc.md
@@ -28,7 +28,7 @@
 | Field | Type | Required | Description |
 | --- | --- | --- | --- |
 | `op` | `"send"` | Yes | Sends one message to one peer or to `"all"`. |
-| `to` | `string` | Yes | Peer id such as `0-Main`, or `"all"` for broadcast. Whitespace is trimmed. |
+| `to` | `string` | Yes | Peer id such as `Main`, or `"all"` for broadcast. Whitespace is trimmed. |
 | `message` | `string` | Yes | Message body. Whitespace is trimmed; empty-after-trim is rejected. |
 | `awaitReply` | `boolean` | No | Wait for prose replies. Defaults to `true` for direct messages and `false` for `to: "all"`. |
 
@@ -44,7 +44,7 @@
 
 ## Flow
 1. `IrcTool.createIf` only constructs the tool when `irc.enabled` is on and the session has both an `AgentRegistry` and `getAgentId` (`packages/coding-agent/src/tools/irc.ts`).
-2. Tool discovery adds another gate in `packages/coding-agent/src/tools/index.ts`: if the caller is `0-Main` and `async.enabled` is off, `irc` is hidden because the main agent cannot talk to concurrent peers in sync mode.
+2. Tool discovery adds another gate in `packages/coding-agent/src/tools/index.ts`: if the caller is `Main` and `async.enabled` is off, `irc` is hidden because the main agent cannot talk to concurrent peers in sync mode.
 3. `execute` resolves the process-global registry and sender id. Missing either returns a text error result instead of throwing.
 4. `op: "list"` calls `registry.listVisibleTo(senderId)`, which exposes every other agent in flat namespace whose status is `running` or `idle` (`packages/coding-agent/src/registry/agent-registry.ts`).
 5. `list` formats human-readable lines and returns `channels` as `['all', ...peerIds]`. These are logical targets only; there is no channel join state.
diff --git a/docs/tools/task.md b/docs/tools/task.md
index 245824836..98026680c 100644
--- a/docs/tools/task.md
+++ b/docs/tools/task.md
@@ -222,4 +222,4 @@ Artifacts and side channels:
 - Branch-mode merge temporarily stashes the parent repo before cherry-picking task branches. A stash-pop conflict is treated as merge failure and leaves recovery state behind.
 - Patch-mode only applies combined root patches if every successful task produced a patch and `git.patch.canApplyText(...)` succeeds.
 - Nested git repos are handled separately from the root repo. They are copied into isolated worktrees, diffed independently, and merged later with `applyNestedPatches(...)` because parent git cannot track their file-level changes.
-- `agent://` ids are numeric-prefixed (`0-Task`, `1-Task`, nested like `0-Parent.0-Child`) by `AgentOutputManager`; this is what prevents artifact collisions across repeated or nested task invocations.
+- `agent://` ids are name-based (`Task` first, `Task-2`/`Task-3` only when the name repeats, nested like `Parent.Child`) by `AgentOutputManager`; this is what prevents artifact collisions across repeated or nested task invocations.
diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 8a4679dbb..8c58cccfe 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -9,6 +9,7 @@
 ### Changed
 
 - Changed the eval `parallel()` / `pipeline()` helpers to drop their `concurrency` argument and run as wide as a `task` tool batch. The worker-pool ceiling now tracks the `task.maxConcurrency` setting (default 32; `0` = run every item at once) resolved live from the host via a new `__concurrency__` bridge, instead of the old per-call `concurrency` option that defaulted to 4 and capped at 16. This stops eval fan-outs from under-using the parallelism the session is configured for.
+- Changed subagent / `agent://` output ids from a numeric prefix scheme (`0-Anna`, `1-Bob`, nested `0-Anna.1-Bob`) to a name-first scheme: the requested name is used verbatim and a `-2`/`-3`/… suffix is added only when the same name recurs within a session (`Anna`, `Anna-2`, `Anna-3`). Nested ids stay grouped under the parent (`Anna.Bob`) and the live task widget renders them as `Anna>Bob`. The main agent's IRC id is now `Main` (was `0-Main`). `AgentOutputManager` still scans existing `.md` outputs on resume so it never reuses a name that would clobber a prior output.
 - Changed resuming a session that belongs to a different project to switch the process into that project's working directory. `pi --resume` and the in-session `/resume` picker now `chdir` into the resumed session's `cwd` and re-scope every cwd-derived input — project dir, **project settings** (`.claude/settings.yml`, `.omp/settings.json`, path-scoped `enabledModels`/`disabledProviders`), plugin roots, capabilities, slash commands, and the ssh tool — so tools, discovery, configuration, and commands all follow the resumed project. The `SessionManager` adopts the resumed session's own `cwd`/session directory on load (rolled back if the switch fails).
 
 ### Fixed
diff --git a/packages/coding-agent/src/async/job-manager.ts b/packages/coding-agent/src/async/job-manager.ts
index bde46c4b1..e1ef6a365 100644
--- a/packages/coding-agent/src/async/job-manager.ts
+++ b/packages/coding-agent/src/async/job-manager.ts
@@ -17,8 +17,8 @@ export interface AsyncJob {
 	resultText?: string;
 	errorText?: string;
 	/**
-	 * Registry id of the agent that registered the job (e.g. "0-Main",
-	 * "3-AuthLoader"). Used by scoped cancel/list APIs so a subagent's teardown
+	 * Registry id of the agent that registered the job (e.g. "Main",
+	 * "AuthLoader"). Used by scoped cancel/list APIs so a subagent's teardown
 	 * does not cancel its parent's jobs. Undefined for callers that don't
 	 * supply an id (e.g. legacy tests, SDK consumers without an agent context).
 	 */
@@ -58,7 +58,7 @@ export interface AsyncJobRegisterOptions {
 /**
  * Filter applied to job query/cancel APIs. With `ownerId`, results are
  * restricted to jobs registered by that agent (registry id from
- * `AgentRegistry`, e.g. "0-Main", "3-AuthLoader").
+ * `AgentRegistry`, e.g. "Main", "AuthLoader").
  */
 export interface AsyncJobFilter {
 	ownerId?: string;
diff --git a/packages/coding-agent/src/prompts/tools/irc.md b/packages/coding-agent/src/prompts/tools/irc.md
index e29d0b5a5..8dbeda10c 100644
--- a/packages/coding-agent/src/prompts/tools/irc.md
+++ b/packages/coding-agent/src/prompts/tools/irc.md
@@ -1,7 +1,7 @@
 Sends short text messages to other live agents in this process and receives their prose replies.
 
 <instruction>
-- The main agent is addressable as `0-Main`. Subagents reuse their task id (e.g. `0-AuthLoader`).
+- The main agent is addressable as `Main`. Subagents reuse their task id (e.g. `AuthLoader`, or `AuthLoader-2` when the name repeats).
 - `op: "list"` returns the current set of visible peers. Use it before sending if you are not sure who is live.
 - `op: "send"` delivers `message` to `to`. `to` may be a specific id or `"all"` to broadcast.
 - The recipient generates the reply via an ephemeral side-channel turn that uses their current model, system prompt, and history — it does **not** wait for the recipient's main loop to be free, so it is safe to IRC an agent that is currently inside a long-running tool call.
@@ -10,7 +10,7 @@ Sends short text messages to other live agents in this process and receives thei
 
 <when_to_use>
 You SHOULD reach for `irc` proactively when continuing alone is wasteful or wrong. When in doubt, prefer messaging.
-- **Unexpected state.** You hit something the original task did not describe — a missing file, a config that contradicts the assignment, an API behaving differently than you were told, a tool failing in a way that suggests the spec is wrong. DM `0-Main` (or the spawning agent) for guidance instead of guessing.
+- **Unexpected state.** You hit something the original task did not describe — a missing file, a config that contradicts the assignment, an API behaving differently than you were told, a tool failing in a way that suggests the spec is wrong. DM `Main` (or the spawning agent) for guidance instead of guessing.
 - **Blocked by another agent.** A peer holds the file/branch/resource you need, has already started the change you are about to make, or owns a decision you depend on. DM that peer (or broadcast to discover who) before duplicating or stepping on work.
 - **Decision points outside your scope.** A genuine fork in the road that the assignment did not pre-decide (e.g. which of two viable APIs to use, whether to refactor adjacent code). Ask the requester rather than picking unilaterally.
 - **Coordination opportunities.** You realize a peer's in-flight work would benefit from yours, or vice-versa.
@@ -25,7 +25,7 @@ These rules apply to both sending and replying.
 - **Use IRC, not terminal tools, to learn about peers.** Do not `grep` artifacts, read other sessions' JSONL files, or shell-poke around to figure out what another agent is doing. DM them — they have the live answer and you do not.
 - **One round-trip is enough.** Replies arrive synchronously when the recipient is reachable. Do not follow up with "did you get my message?" — they did. If `delivered` is empty or the result was `failed`, the peer is unavailable; move on or report the blocker, do not retry in a loop.
 - **Stay terse.** A DM is a chat message, not a memo. One question per send when you can. Share file paths and artifacts via `local://` / `memory://` / `artifact://` URLs instead of pasting blobs.
-- **Address peers by id.** Use the exact id from `op: "list"` (e.g. `0-AuthLoader`, `0-Main`). Do not invent friendly names.
+- **Address peers by id.** Use the exact id from `op: "list"` (e.g. `AuthLoader`, `Main`). Do not invent friendly names.
 - **Do not IRC for things a tool would answer.** If a `read`, `grep`, or build command would resolve the question, do that first.
 - **When you receive an IRC message, answer it before continuing.** The recipient injects the question + your auto-reply into your history; address it directly, do not repeat it back to the user.
 </etiquette>
@@ -39,11 +39,11 @@ These rules apply to both sending and replying.
 # List peers
 `{"op": "list"}`
 # Direct message to the main agent (waits for prose reply)
-`{"op": "send", "to": "0-Main", "message": "Should I prefer JWT or session cookies for the auth flow?"}`
+`{"op": "send", "to": "Main", "message": "Should I prefer JWT or session cookies for the auth flow?"}`
 # Unexpected state — ask the originator
-`{"op": "send", "to": "0-Main", "message": "Assignment says edit src/auth/jwt.ts but the file does not exist. Is the new path src/server/auth/jwt.ts?"}`
+`{"op": "send", "to": "Main", "message": "Assignment says edit src/auth/jwt.ts but the file does not exist. Is the new path src/server/auth/jwt.ts?"}`
 # Blocked by a peer — ask them directly
-`{"op": "send", "to": "0-AuthLoader", "message": "Are you still touching src/server/auth.ts? I need to add a 401 path; OK to proceed or should I wait?"}`
+`{"op": "send", "to": "AuthLoader", "message": "Are you still touching src/server/auth.ts? I need to add a 401 path; OK to proceed or should I wait?"}`
 # Broadcast to discover who owns something (no replies, just informs them)
 `{"op": "send", "to": "all", "message": "About to refactor src/server/middleware/*. Anyone already in there?", "awaitReply": false}`
 </examples>
diff --git a/packages/coding-agent/src/prompts/tools/task.md b/packages/coding-agent/src/prompts/tools/task.md
index c8b422b48..252b79381 100644
--- a/packages/coding-agent/src/prompts/tools/task.md
+++ b/packages/coding-agent/src/prompts/tools/task.md
@@ -2,7 +2,7 @@ Launches subagents to parallelize workflows.
 
 {{#if asyncEnabled}}
 - Results are delivered automatically when complete.
-- The tool result lists the assigned task ids (e.g. `0-AuthLoader`) — those are the live agent ids.
+- The tool result lists the assigned task ids (e.g. `AuthLoader`) — those are the live agent ids.
 {{#if ircEnabled}}
 - Coordinate with running tasks via `irc` using those ids. `job cancel` terminates a task and **cannot carry a message** — only use it for stalled/abandoned work.
 - If genuinely blocked on completion, wait with `job poll`; otherwise keep working.
diff --git a/packages/coding-agent/src/registry/agent-registry.ts b/packages/coding-agent/src/registry/agent-registry.ts
index ae4abe19c..271b9d90b 100644
--- a/packages/coding-agent/src/registry/agent-registry.ts
+++ b/packages/coding-agent/src/registry/agent-registry.ts
@@ -8,7 +8,7 @@
 
 import type { AgentSession } from "../session/agent-session";
 
-export const MAIN_AGENT_ID = "0-Main";
+export const MAIN_AGENT_ID = "Main";
 
 export type AgentStatus = "running" | "idle" | "completed" | "aborted";
 export type AgentKind = "main" | "sub";
diff --git a/packages/coding-agent/src/sdk.ts b/packages/coding-agent/src/sdk.ts
index 5b2b7f85d..7f5140be9 100644
--- a/packages/coding-agent/src/sdk.ts
+++ b/packages/coding-agent/src/sdk.ts
@@ -323,13 +323,13 @@ export interface CreateAgentSessionOptions {
 	parentHindsightSessionState?: HindsightSessionState;
 	/** Parent Mnemopi state to alias for subagent memory tools. */
 	parentMnemopiSessionState?: MnemopiSessionState;
-	/** Pre-allocated agent identity for IRC routing. Default: "0-Main" for top-level, parentTaskPrefix-derived for sub. */
+	/** Pre-allocated agent identity for IRC routing. Default: "Main" for top-level, parentTaskPrefix-derived for sub. */
 	agentId?: string;
 	/** Display name for the agent in IRC. Default: "main" or "sub". */
 	agentDisplayName?: string;
 	/** Optional shared agent registry for IRC routing. Default: AgentRegistry.global(). */
 	agentRegistry?: AgentRegistry;
-	/** Parent task ID prefix for nested artifact naming (e.g., "6-Extensions") */
+	/** Parent task ID prefix for nested artifact naming (e.g., "Extensions") */
 	parentTaskPrefix?: string;
 	/** Inherited eval executor session id for subagents sharing parent eval state. */
 	parentEvalSessionId?: string;
diff --git a/packages/coding-agent/src/session/agent-session.ts b/packages/coding-agent/src/session/agent-session.ts
index ea38e483d..6654b4285 100644
--- a/packages/coding-agent/src/session/agent-session.ts
+++ b/packages/coding-agent/src/session/agent-session.ts
@@ -358,7 +358,7 @@ export interface AgentSessionConfig {
 	 * **MUST NOT** dispose it on their own teardown.
 	 */
 	ownedAsyncJobManager?: AsyncJobManager;
-	/** Agent identity (registry id like "0-Main" or "3-Alice") used for IRC routing. */
+	/** Agent identity (registry id like "Main" or "Alice") used for IRC routing. */
 	agentId?: string;
 	/** Shared agent registry (for forwarding IRC observations to the main session UI). */
 	agentRegistry?: AgentRegistry;
diff --git a/packages/coding-agent/src/task/output-manager.ts b/packages/coding-agent/src/task/output-manager.ts
index cc64ff402..46d6593c0 100644
--- a/packages/coding-agent/src/task/output-manager.ts
+++ b/packages/coding-agent/src/task/output-manager.ts
@@ -1,29 +1,28 @@
 /**
  * Session-scoped manager for agent output IDs.
  *
- * Ensures unique output IDs across task tool invocations within a session.
- * Prefixes each ID with a sequential number (e.g., "0-AuthProvider", "1-AuthApi").
- * If a parent prefix is provided, IDs are nested (e.g., "0-Auth.1-Subtask").
+ * Keeps every subagent output id unique within a session without polluting the
+ * common case with bookkeeping. A requested name is used verbatim the first
+ * time it appears; only a *repeated* name gets a numeric suffix to disambiguate
+ * it (e.g. "Anna", "Anna-2", "Anna-3"). When a parent prefix is configured, ids
+ * are nested under it (e.g. "Anna.Bob") so hierarchical outputs stay grouped.
  *
- * This enables reliable agent:// URL resolution and prevents artifact collisions.
+ * This enables reliable agent:// URL resolution and prevents artifact
+ * collisions across repeated or nested task invocations.
  */
 import * as fs from "node:fs/promises";
 
-function escapeRegExp(value: string): string {
-	return value.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
-}
-
 /**
  * Manages agent output ID allocation to ensure uniqueness.
  *
- * Each allocated ID gets a numeric prefix based on allocation order.
- * If configured with a parent prefix, the numeric prefix is appended after
- * the parent (e.g., "0-Parent.0-Child").
- * On resume, scans existing files to find the next available index.
+ * The first allocation of a given name keeps the name as-is; subsequent
+ * allocations of the same name get a `-2`, `-3`, … suffix. On resume, scans
+ * existing output files so previously written outputs are never overwritten.
  */
 export class AgentOutputManager {
-	#nextId = 0;
 	#initialized = false;
+	/** Final ids already handed out, relative to this manager's scope. */
+	readonly #taken = new Set<string>();
 	readonly #getArtifactsDir: () => string | null;
 	readonly #parentPrefix: string | undefined;
 
@@ -33,8 +32,8 @@ export class AgentOutputManager {
 	}
 
 	/**
-	 * Scan existing agent output files to find the next available ID.
-	 * This ensures we don't overwrite outputs when resuming a session.
+	 * Seed the taken-id set from output files already on disk so a resumed
+	 * session never reuses a name that would clobber a prior subagent's output.
 	 */
 	async #ensureInitialized(): Promise<void> {
 		if (this.#initialized) return;
@@ -50,31 +49,41 @@ export class AgentOutputManager {
 			return; // Directory doesn't exist yet
 		}
 
-		const pattern = this.#parentPrefix
-			? new RegExp(`^${escapeRegExp(this.#parentPrefix)}\\.(\\d+)-.*\\.md$`)
-			: /^(\d+)-.*\.md$/;
-
-		let maxId = -1;
+		const prefix = this.#parentPrefix ? `${this.#parentPrefix}.` : "";
 		for (const file of files) {
-			const match = file.match(pattern);
-			if (match) {
-				const id = Number.parseInt(match[1], 10);
-				if (id > maxId) maxId = id;
+			if (!file.endsWith(".md")) continue;
+			let rest = file.slice(0, -3); // drop ".md"
+			if (prefix) {
+				if (!rest.startsWith(prefix)) continue;
+				rest = rest.slice(prefix.length);
 			}
+			// Requested ids never contain "."; a dot marks a nested child, so this
+			// manager only owns the first segment of whatever remains.
+			const dot = rest.indexOf(".");
+			const segment = dot === -1 ? rest : rest.slice(0, dot);
+			if (segment) this.#taken.add(segment);
 		}
-		this.#nextId = maxId + 1;
+	}
+
+	/** Pick the first free name (base, then `base-2`, `base-3`, …) and reserve it. */
+	#allocateUnique(id: string): string {
+		let candidate = id;
+		for (let n = 2; this.#taken.has(candidate); n++) {
+			candidate = `${id}-${n}`;
+		}
+		this.#taken.add(candidate);
+		return this.#parentPrefix ? `${this.#parentPrefix}.${candidate}` : candidate;
 	}
 
 	/**
-	 * Allocate a unique ID with numeric prefix.
+	 * Allocate a unique ID.
 	 *
-	 * @param id Requested ID (e.g., "AuthProvider")
-	 * @returns Unique ID with prefix (e.g., "0-AuthProvider")
+	 * @param id Requested ID (e.g., "Anna")
+	 * @returns Unique ID ("Anna" first, then "Anna-2", "Anna-3", …)
 	 */
 	async allocate(id: string): Promise<string> {
 		await this.#ensureInitialized();
-		const prefix = this.#parentPrefix ? `${this.#parentPrefix}.` : "";
-		return `${prefix}${this.#nextId++}-${id}`;
+		return this.#allocateUnique(id);
 	}
 
 	/**
@@ -85,23 +94,6 @@ export class AgentOutputManager {
 	 */
 	async allocateBatch(ids: string[]): Promise<string[]> {
 		await this.#ensureInitialized();
-		const prefix = this.#parentPrefix ? `${this.#parentPrefix}.` : "";
-		return ids.map(id => `${prefix}${this.#nextId++}-${id}`);
-	}
-
-	/**
-	 * Get the next ID that would be allocated (without allocating).
-	 */
-	async peekNextIndex(): Promise<number> {
-		await this.#ensureInitialized();
-		return this.#nextId;
-	}
-
-	/**
-	 * Reset state (primarily for testing).
-	 */
-	reset(): void {
-		this.#nextId = 0;
-		this.#initialized = false;
+		return ids.map(id => this.#allocateUnique(id));
 	}
 }
diff --git a/packages/coding-agent/src/task/render.ts b/packages/coding-agent/src/task/render.ts
index a7473d986..5babac27e 100644
--- a/packages/coding-agent/src/task/render.ts
+++ b/packages/coding-agent/src/task/render.ts
@@ -128,15 +128,10 @@ function formatJsonScalar(value: unknown, _theme: Theme): string {
 }
 
 function formatTaskId(id: string): string {
+	// Ids are name-based (e.g. "Anna", "Anna-2"); a "." separates nesting levels
+	// (e.g. "Anna.Bob"). Render the hierarchy with a ">" breadcrumb.
 	const segments = id.split(".");
-	if (segments.length < 2) return id;
-
-	const parsed = segments.map(segment => segment.match(/^(\d+)-(.+)$/));
-	if (parsed.some(match => !match)) return id;
-
-	const indices = parsed.map(match => match![1]).join(".");
-	const labels = parsed.map(match => match![2]).join(">");
-	return `${indices} ${labels}`;
+	return segments.length < 2 ? id : segments.join(">");
 }
 
 const MISSING_YIELD_WARNING_PREFIX = "SYSTEM WARNING: Subagent exited without calling yield tool";
diff --git a/packages/coding-agent/src/tools/index.ts b/packages/coding-agent/src/tools/index.ts
index 973823980..8467b7349 100644
--- a/packages/coding-agent/src/tools/index.ts
+++ b/packages/coding-agent/src/tools/index.ts
@@ -159,7 +159,7 @@ export interface ToolSession {
 	getHindsightSessionState?: () => HindsightSessionState | undefined;
 	/** Get Mnemopi runtime state for this agent session. */
 	getMnemopiSessionState?: () => MnemopiSessionState | undefined;
-	/** Agent identity used for IRC routing. Returns the registry id (e.g. "0-Main", "0-AuthLoader"). */
+	/** Agent identity used for IRC routing. Returns the registry id (e.g. "Main", "AuthLoader"). */
 	getAgentId?: () => string | null;
 	/** Look up a registered tool by name (used by the eval js backend's tool bridge). */
 	getToolByName?: (name: string) => AgentTool | undefined;
diff --git a/packages/coding-agent/test/task/output-manager.test.ts b/packages/coding-agent/test/task/output-manager.test.ts
new file mode 100644
index 000000000..50fef2440
--- /dev/null
+++ b/packages/coding-agent/test/task/output-manager.test.ts
@@ -0,0 +1,64 @@
+import { describe, expect, it } from "bun:test";
+import * as path from "node:path";
+import { AgentOutputManager } from "@oh-my-pi/pi-coding-agent/task/output-manager";
+import { TempDir } from "@oh-my-pi/pi-utils";
+
+// Contract: subagent output ids are the requested name, used verbatim the first
+// time and suffixed (`-2`, `-3`, …) only when the same name recurs. A parent
+// prefix nests ids under it. On resume the manager scans existing `.md` outputs
+// so it never reuses a name that would clobber a previously written output.
+
+describe("AgentOutputManager", () => {
+	it("uses the requested name verbatim and suffixes only on repeat", async () => {
+		const mgr = new AgentOutputManager(() => null);
+
+		expect(await mgr.allocate("Anna")).toBe("Anna");
+		expect(await mgr.allocate("Anna")).toBe("Anna-2");
+		expect(await mgr.allocate("Anna")).toBe("Anna-3");
+		// A distinct name is untouched — no prefix, no suffix.
+		expect(await mgr.allocate("Bob")).toBe("Bob");
+	});
+
+	it("de-duplicates within a batch while preserving order", async () => {
+		const mgr = new AgentOutputManager(() => null);
+
+		expect(await mgr.allocateBatch(["Auth", "Auth", "Api", "Auth"])).toEqual(["Auth", "Auth-2", "Api", "Auth-3"]);
+	});
+
+	it("nests ids under a parent prefix and still suffixes repeats", async () => {
+		const mgr = new AgentOutputManager(() => null, { parentPrefix: "Anna" });
+
+		expect(await mgr.allocate("Bob")).toBe("Anna.Bob");
+		expect(await mgr.allocate("Bob")).toBe("Anna.Bob-2");
+		expect(await mgr.allocate("Carol")).toBe("Anna.Carol");
+	});
+
+	it("scans existing output files so a resume never clobbers prior outputs", async () => {
+		using tmp = TempDir.createSync("@omp-output-manager-");
+		const dir = tmp.path();
+		await Bun.write(path.join(dir, "Anna.md"), "prior");
+		await Bun.write(path.join(dir, "Anna-2.md"), "prior");
+		// Unrelated tool artifacts (numeric `.log` ids) must not be mistaken for names.
+		await Bun.write(path.join(dir, "7.bash.log"), "noise");
+
+		const mgr = new AgentOutputManager(() => dir);
+
+		expect(await mgr.allocate("Anna")).toBe("Anna-3");
+		// A name with no file on disk is still pristine.
+		expect(await mgr.allocate("Bob")).toBe("Bob");
+	});
+
+	it("only counts files within its own prefix scope on resume", async () => {
+		using tmp = TempDir.createSync("@omp-output-manager-");
+		const dir = tmp.path();
+		await Bun.write(path.join(dir, "Anna.Bob.md"), "child");
+		await Bun.write(path.join(dir, "Anna.Bob.Carol.md"), "grandchild");
+		// A different parent's child must be ignored by Anna's manager.
+		await Bun.write(path.join(dir, "Other.Bob.md"), "elsewhere");
+
+		const mgr = new AgentOutputManager(() => dir, { parentPrefix: "Anna" });
+
+		expect(await mgr.allocate("Bob")).toBe("Anna.Bob-2");
+		expect(await mgr.allocate("Dave")).toBe("Anna.Dave");
+	});
+});
diff --git a/packages/coding-agent/test/task/render-nested-live.test.ts b/packages/coding-agent/test/task/render-nested-live.test.ts
index 9fc3ddb33..fac5e4431 100644
--- a/packages/coding-agent/test/task/render-nested-live.test.ts
+++ b/packages/coding-agent/test/task/render-nested-live.test.ts
@@ -99,15 +99,15 @@ describe("task renderer: nested live rendering", () => {
 
 	it("renders completed nested task results stored in extractedToolData.task while parent is in-progress", async () => {
 		const parent = makeRunningProgress({
-			id: "1-Parent",
+			id: "Parent",
 			recentTools: [{ tool: "task", args: "", endMs: Date.now() }],
 			extractedToolData: {
 				task: [
 					{
 						projectAgentsDir: null,
 						results: [
-							makeCompletedSubResult("1-Parent.0-AlphaSub", "Alpha child"),
-							makeCompletedSubResult("1-Parent.1-BetaSub", "Beta child"),
+							makeCompletedSubResult("Parent.AlphaSub", "Alpha child"),
+							makeCompletedSubResult("Parent.BetaSub", "Beta child"),
 						],
 						totalDurationMs: 1000,
 					} satisfies TaskToolDetails,
@@ -119,12 +119,12 @@ describe("task renderer: nested live rendering", () => {
 
 		// Parent label is intact.
 		expect(text).toContain("Parent Level 1 work");
-		// Both nested completed children labels surface (formatTaskId collapses
-		// dotted ids → "1.0 Parent>AlphaSub").
+		// Both nested completed children labels surface (formatTaskId renders the
+		// dotted hierarchy as a "Parent>AlphaSub" breadcrumb).
 		expect(text).toContain("Alpha child");
 		expect(text).toContain("Beta child");
-		expect(text).toContain("1.0 Parent>AlphaSub");
-		expect(text).toContain("1.1 Parent>BetaSub");
+		expect(text).toContain("Parent>AlphaSub");
+		expect(text).toContain("Parent>BetaSub");
 	});
 
 	it("renders the in-flight nested task snapshot (progress[]) before the call ends", async () => {
@@ -133,12 +133,12 @@ describe("task renderer: nested live rendering", () => {
 			results: [],
 			totalDurationMs: 0,
 			progress: [
-				makeRunningSubProgress("2-Parent.0-GammaSub", "Gamma child running"),
-				makeRunningSubProgress("2-Parent.1-DeltaSub", "Delta child running"),
+				makeRunningSubProgress("Parent.GammaSub", "Gamma child running"),
+				makeRunningSubProgress("Parent.DeltaSub", "Delta child running"),
 			],
 		};
 		const parent = makeRunningProgress({
-			id: "2-Parent",
+			id: "Parent",
 			currentTool: "task",
 			currentToolStartMs: Date.now(),
 			inflightTaskDetails: inflight,
@@ -149,8 +149,8 @@ describe("task renderer: nested live rendering", () => {
 		expect(text).toContain("Parent Level 1 work");
 		expect(text).toContain("Gamma child running");
 		expect(text).toContain("Delta child running");
-		expect(text).toContain("2.0 Parent>GammaSub");
-		expect(text).toContain("2.1 Parent>DeltaSub");
+		expect(text).toContain("Parent>GammaSub");
+		expect(text).toContain("Parent>DeltaSub");
 	});
 
 	it("combines completed and in-flight nested snapshots in one tree", async () => {
@@ -160,7 +160,7 @@ describe("task renderer: nested live rendering", () => {
 				task: [
 					{
 						projectAgentsDir: null,
-						results: [makeCompletedSubResult("3.0-EpsilonSub", "Epsilon done")],
+						results: [makeCompletedSubResult("Parent.EpsilonSub", "Epsilon done")],
 						totalDurationMs: 1000,
 					} satisfies TaskToolDetails,
 				],
@@ -169,7 +169,7 @@ describe("task renderer: nested live rendering", () => {
 				projectAgentsDir: null,
 				results: [],
 				totalDurationMs: 0,
-				progress: [makeRunningSubProgress("3.1-ZetaSub", "Zeta running")],
+				progress: [makeRunningSubProgress("Parent.ZetaSub", "Zeta running")],
 			},
 		});