docs(agents): standardize task filenames on issue-number prefix

.github/agents/dev-loop.agent.md

@@ -162,7 +162,7 @@ Break the approved design into bite-sized tasks (2-5 minutes each). Each task in
 - Exact test commands with expected output
 - Commit message
 
-The file format, slug convention, and lifecycle for `tasks/<feature>-plan.md`
+The file format, slug convention, and lifecycle for `tasks/<issue#>-<slug>-plan.md`
 are defined authoritatively in **`plan.agent.md` § Saving the Plan to
 `tasks/`**. Do not duplicate that spec here.
 
@@ -172,17 +172,17 @@ updates the existing file in place** -- expand each skeleton checklist
 item into the bite-sized tasks described above. Treat unchecked items as
 the next tasks to execute.
 
-If `tasks/<feature-name>-prd.md` exists (written by `@prd`), ingest it as
+If `tasks/<issue#>-<slug>-prd.md` exists (written by `@prd`), ingest it as
 authoritative requirements input alongside the GitHub issue.
 
-If `tasks/<feature-name>-plan.md` does not exist (e.g., the issue was
+If `tasks/<issue#>-<slug>-plan.md` does not exist (e.g., the issue was
 filed manually, bypassing `@plan`), create it now using the format from
 `plan.agent.md` § Saving the Plan to `tasks/`.
 
 After expansion, get user approval and update the GitHub issue with the
 expanded task checklist.
 
-**Exit criteria:** Plan saved/updated in `tasks/<feature-name>-plan.md`,
+**Exit criteria:** Plan saved/updated in `tasks/<issue#>-<slug>-plan.md`,
 user approved, issue updated.
 
 ### Phase 3 -- TDD (Red -> Green)

.github/agents/plan.agent.md

@@ -35,13 +35,13 @@ MUST present it and get approval.
 
 You MUST complete these steps in order:
 
-1. **Explore project context** — check files, docs, recent commits; **scan `tasks/`** for prior PRDs or plans on the same feature slug (`tasks/<feature>-prd.md`, `tasks/<feature>-plan.md`). If found, surface them and offer to refine the existing design rather than propose a brand-new one.
+1. **Explore project context** — check files, docs, recent commits; **scan `tasks/`** for prior PRDs or plans on the same feature (`tasks/<issue#>-<slug>-prd.md`, `tasks/<issue#>-<slug>-plan.md`; fall back to a glob `tasks/*-<slug>-*.md` when the issue number is unknown). If found, surface them and offer to refine the existing design rather than propose a brand-new one.
 2. **Ask clarifying questions** — one at a time, understand purpose/constraints/success criteria
 3. **Propose 2-3 approaches** — with trade-offs and your recommendation
 4. **Present design** — in sections scaled to complexity, get user approval after each section
 5. **Declare the Evidence Plan** — every plan must name the change type, the artifact format, the exact capture command, and the entry-point file the reviewer will open (see "Evidence Plan" below). The dev-loop's Phase 5b verifies the produced artifact matches this declaration.
 6. **Create GitHub issue** — save the approved design as a GitHub issue (the primary output)
-7. **Save the plan to `tasks/<feature>-plan.md`** — durable, in-repo artifact mirroring the issue body. Format defined in **Saving the Plan to `tasks/`** below. This is the single authoritative spec for the `tasks/<feature>-plan.md` file -- `@dev-loop` Phase 2 *resumes / expands* this file, it does not redefine the format.
+7. **Save the plan to `tasks/<issue#>-<slug>-plan.md`** — durable, in-repo artifact mirroring the issue body. Format defined in **Saving the Plan to `tasks/`** below. This is the single authoritative spec for the `tasks/<issue#>-<slug>-plan.md` file -- `@dev-loop` Phase 2 *resumes / expands* this file, it does not redefine the format.
 8. **Transition to implementation** — hand off to `@dev-loop` for the full quality cycle
 
 ## The Process
@@ -139,7 +139,7 @@ attestation markdown still serves as the entry-point file.
 
 ## Saving the Plan to `tasks/`
 
-**This section is the authoritative spec for `tasks/<feature>-plan.md`.**
+**This section is the authoritative spec for `tasks/<issue#>-<slug>-plan.md`.**
 `@dev-loop` Phase 2 references this section by name -- it does not redefine
 the file format.
 
@@ -150,9 +150,14 @@ and expands it.
 
 ### Path and Slug Convention
 
-- Path: `tasks/<feature>-plan.md` at the repo root.
-- `<feature>` = `<issue#>-<short-description>` matching the GitHub issue
-  number and the eventual feature branch name (`feat/<issue#>-<short-description>`).
+- Path: `tasks/<issue#>-<slug>-plan.md` at the repo root.
+- `<issue#>` = the GitHub issue number; `<slug>` = a short kebab-case
+  description. Together `<issue#>-<slug>` is the shared identifier carried by
+  the GitHub issue, the feature branch (`feat/<issue#>-<slug>`), and the PR.
+  Derive both from the current branch name.
+- Look up an existing plan by the exact `tasks/<issue#>-<slug>-plan.md` first,
+  then fall back to a glob `tasks/*-<slug>-plan.md`, then to a bare
+  `tasks/<slug>-plan.md` for legacy files predating the issue-number prefix.
 - Create the `tasks/` directory if it does not yet exist.
 - See `tasks/README.md` (consumer-owned) for the project's local
   conventions; do not contradict it.
@@ -164,7 +169,7 @@ and expands it.
 
 - Issue: https://github.com/<owner>/<repo>/issues/<n>
 - PR:    (filled in once the PR exists)
-- Slug:  <feature>
+- Slug:  <issue#>-<slug>
 
 ## Overview
 [1-2 sentence description -- mirrors the issue body]

.github/agents/prd.agent.md

@@ -12,13 +12,13 @@ This agent uses the default model. No specific model override is required.
 
 Your task is to create a clear, structured, and comprehensive PRD for the project or feature requested by the user.
 
-Save the PRD to `tasks/<feature-name>-prd.md` at the repo root. Create the `tasks/` directory first if it does not yet exist (`mkdir tasks` or `New-Item -ItemType Directory -Path tasks -Force`). If the user specifies a different location, use that instead.
+Save the PRD to `tasks/<issue#>-<slug>-prd.md` at the repo root, where `<issue#>` is the GitHub issue number and `<slug>` is a short kebab-case description -- the same `<issue#>-<slug>` identifier used by the feature branch (`feat/<issue#>-<slug>`). Derive both from the current branch name when one exists. If no issue has been filed yet (a PRD spike), save to the bare `tasks/<slug>-prd.md` and rename it to add the `<issue#>-` prefix once the issue is created. Create the `tasks/` directory first if it does not yet exist (`mkdir tasks` or `New-Item -ItemType Directory -Path tasks -Force`). If the user specifies a different location, use that instead.
 
 Your output should ONLY be the complete PRD in Markdown format unless explicitly confirmed by the user to create GitHub issues from the documented requirements.
 
 ## Instructions for Creating the PRD
 
-0. **Check for an existing PRD**: At the start of the workflow, look for `tasks/<feature-name>-prd.md` using the slug the user has chosen (or one derivable from the branch name `feat/<issue#>-<feature-name>`). If a PRD already exists for this feature, read it and offer to **update** it rather than overwrite. Surface the existing content to the user and ask whether to revise sections in place, append new sections, or start fresh.
+0. **Check for an existing PRD**: At the start of the workflow, look for an existing PRD before writing a new one. Derive `<issue#>` and `<slug>` from the current branch (`feat/<issue#>-<slug>`) and check `tasks/<issue#>-<slug>-prd.md` first. If not found, fall back to a glob `tasks/*-<slug>-prd.md` (issue number differs or is unknown), then to the bare `tasks/<slug>-prd.md` for legacy files predating the issue-number prefix. If a PRD already exists for this feature, read it and offer to **update** it rather than overwrite. Surface the existing content to the user and ask whether to revise sections in place, append new sections, or start fresh.
 
 1. **Ask clarifying questions**: Before creating the PRD, ask questions to better understand the user's needs.
 

tasks/README.md

@@ -11,16 +11,23 @@ session and the project can be reconstructed from these files alone.
 
 ## Filename Convention
 
-One feature per slug. Each slug matches its branch name
-(`feat/<issue#>-<feature>`), so the PRD, plan, GitHub issue, branch, and PR
-all share an identifier.
+One feature per `<issue#>-<slug>` identifier, shared by the PRD, plan, GitHub
+issue, branch (`feat/<issue#>-<slug>`), and PR:
+
+- `<issue#>` -- the GitHub issue number; the leading token is identical to the
+  branch name, so `tasks/` sorts naturally by issue number.
+- `<slug>` -- a short kebab-case description.
 
 | File                          | Written by               | Purpose                                              |
 |-------------------------------|--------------------------|------------------------------------------------------|
-| `<feature>-prd.md`            | `@prd` agent             | Product requirements: user stories, acceptance criteria, metrics. |
-| `<feature>-plan.md`           | `@dev-loop` Phase 2      | Implementation plan: ordered tasks with file paths, code snippets, commit messages. |
+| `<issue#>-<slug>-prd.md`      | `@prd` agent             | Product requirements: user stories, acceptance criteria, metrics. |
+| `<issue#>-<slug>-plan.md`     | `@dev-loop` Phase 2      | Implementation plan: ordered tasks with file paths, code snippets, commit messages. |
 | `MIGRATION.md`                | `Consolidate-Tasks.ps1`  | Audit trail of files imported from legacy locations. |
 
+A PRD spike filed before an issue exists may use the bare `<slug>-prd.md` and
+get renamed to add the `<issue#>-` prefix once the issue is created. Legacy
+files predating this convention may also appear as a bare `<slug>-{prd,plan}.md`.
+
 ## Cross-Referencing
 
 Each artifact should link to its companion GitHub issue and PR. Recommended
@@ -31,11 +38,11 @@ top-of-file header:
 
 - Issue: https://github.com/<owner>/<repo>/issues/<n>
 - PR:    https://github.com/<owner>/<repo>/pull/<m>
-- Slug:  <feature>
+- Slug:  <issue#>-<slug>
 ```
 
 When a PRD or plan references stories or tasks by identifier, prefer the
-GitHub issue number once it exists; use a local `<feature>-NN` form only
+GitHub issue number once it exists; use a local `<issue#>-<slug>-NN` form only
 until the issues are filed.
 
 ## Sync Immunity
@@ -49,8 +56,8 @@ so its contents are **never** touched by upstream sync. Edit freely; the next
 The repo-root script `Consolidate-Tasks.ps1` imports historical spec
 artifacts into this directory:
 
-- `docs/designs/*.md`  -> moved (`git mv`) and renamed to `<feature>-plan.md`
-- `docs/prd/*.md`      -> moved (`git mv`) and renamed to `<feature>-prd.md`
+- `docs/designs/*.md`  -> moved (`git mv`) and renamed to `<slug>-plan.md`
+- `docs/prd/*.md`      -> moved (`git mv`) and renamed to `<slug>-prd.md`
 - Root `PRD.md`, `plan.md`, `IMPLEMENTATION_PLAN.md` -> moved
 - `~/.copilot/session-state/*/plan.md` -> copied (repo-scoped via the session-store DB), default ON
 - `~/.claude/...` session notes -> copied, opt-in (`-IncludeClaudeSessions`)