[instructions] Sync instruction files with release v0.84.2

.github/aw/create-agentic-workflow.md

@@ -126,10 +126,9 @@ Use [triggers.md](triggers.md), [workflow-patterns.md](workflow-patterns.md), an
 
 ### 3. Keep permissions read-only
 
-The main agent job must stay read-only.
+See [workflow-constraints.md](workflow-constraints.md) for the read-only security posture. Specific to workflow creation:
 
 - Do not grant `issues: write`, `pull-requests: write`, or `contents: write` to the agent job.
-- Route GitHub writes through `safe-outputs:`.
 - When targeting the Copilot coding agent, recommend `permissions: { copilot-requests: write }` so Copilot can authenticate with `${{ github.token }}`.
 - If the user asks for direct writes, explain why the safe-output pattern is required.
 

.github/aw/safe-outputs-content.md

@@ -104,6 +104,8 @@ description: Safe-output reference for issue, discussion, comment, and pull requ
 
   `close-older-discussions: true` closes up to 10 older discussions matching the same title prefix or labels as "OUTDATED" with a comment linking to the new one. Requires `title-prefix` or `labels`.
 
+  `create_discussion` output validation requires `body` minimum length: **64** characters.
+
 - `close-discussion:` - Close discussions with comment and resolution
 
   ```yaml

.github/aw/syntax-agentic.md

@@ -22,7 +22,7 @@ description: Agentic workflow specific frontmatter fields for GitHub Agentic Wor
 - **`strict:`** - Enable enhanced validation for production workflows (boolean, defaults to `true`; strongly recommended)
   - Prefer `strict: true`; `strict: false` is dangerous, should be extremely rare, and must be carefully security reviewed before use
 - **`model:`** - Top-level LLM model override applied to the agentic engine (string). Takes precedence over `engine.model` when both are set. Accepts full model IDs (e.g. `claude-3-5-sonnet-20241022`, `gpt-5.4`) and aliases (e.g. `small`, `large`). The engine-level `engine.model` is a deprecated alias — prefer this top-level field; run `gh aw fix` to migrate.
-- **`max-turns:`** - AWF turn cap applied consistently across all agentic engines (integer or expression, e.g. `${{ inputs.max-turns }}`). The engine-level `engine.max-turns` is a deprecated alias kept for backward compatibility — prefer this top-level field. Not supported by the `gemini` engine.
+- **`max-turns:`** - AWF turn cap applied consistently across all agentic engines (integer or expression, e.g. `${{ inputs.max-turns }}`). The engine-level `engine.max-turns` is a deprecated alias kept for backward compatibility — prefer this top-level field.
 - **`max-runs:`** - Deprecated legacy alias for the AWF invocation cap (`apiProxy.maxRuns`, defaults to `500` when omitted). Use `max-turns` instead; run `gh aw fix` to migrate.
 - **`max-ai-credits:`** - Per-run AI Credits (AIC) budget enforced by the AWF firewall (integer or `K`/`M` short-form string like `100M`; default `1000`). Set a negative value to disable enforcement and token steering. See [token-optimization.md](token-optimization.md).
 - **`max-turn-cache-misses:`** - Maximum consecutive AWF cache misses allowed before the API proxy blocks further requests (integer, default `5`). Maps to `apiProxy.maxCacheMisses`; precedence is frontmatter → `GH_AW_DEFAULT_MAX_TURN_CACHE_MISSES` env override → built-in default.

.github/aw/syntax-engine.md

@@ -32,7 +32,7 @@ See [syntax-agentic.md](syntax-agentic.md) for the full frontmatter field index.
         key = "value"
     ```
 
-  - **`gemini` engine**: Google Gemini CLI. Requires `GEMINI_API_KEY` secret. Does not support `max-turns`, `web-fetch`, or `web-search`. Supports AWF firewall and LLM gateway.
+  - **`gemini` engine**: Google Gemini CLI. Requires `GEMINI_API_KEY` secret. Does not support `web-search`. Supports AWF firewall and LLM gateway.
   - **`antigravity` engine** (experimental): Google Antigravity CLI in headless mode. Requires `ANTIGRAVITY_API_KEY` secret; model via `model:` (maps to `ANTIGRAVITY_MODEL`). Supports `max-turns`, tools allow-list, AWF firewall, and LLM gateway. Does not support `web-search`, `max-continuations`, or native agent files (agent content is prepended to the prompt).
   - **`opencode` engine** (experimental): Provider-agnostic, open-source AI coding agent (BYOK). Defaults to Copilot routing via `COPILOT_GITHUB_TOKEN` (or `${{ github.token }}` with `copilot-requests` feature). Supports 75+ models via `provider/model` format. Supports AWF firewall and LLM gateway.
   - **`engine.driver:`** — canonical field to run a custom inner driver script instead of the engine's built-in CLI. For the `pi` engine it launches the driver directly with Node.js (e.g. built-in `pi_agent_core_driver.cjs`, or a workspace-relative path like `.github/drivers/pi_agent_core_driver_sample_node.cjs`); the driver must emit JSONL compatible with `parse_pi_log.cjs` so step summaries and token tracking keep working. Accepts a bare basename (resolved from the setup-action directory) or a workspace-relative path; no absolute paths, no `..`, only `.js`/`.cjs`/`.mjs` (pi).

.github/aw/update-agentic-workflow.md

@@ -45,11 +45,11 @@ Use [workflow-editing.md](workflow-editing.md) as the source of truth.
 - make the smallest possible change
 - preserve existing style and structure unless reorganization is required
 - do not rewrite unrelated frontmatter sections
-- keep the agent job read-only
 - when targeting the Copilot coding agent, recommend `permissions: { copilot-requests: write }` for Copilot authentication
-- use `safe-outputs:` for writes
 - prefer `toolsets:` for GitHub tools
 
+See [workflow-constraints.md](workflow-constraints.md) for the read-only security posture (keep the agent job read-only, route writes through `safe-outputs:`).
+
 ## Common Update Categories
 
 See [workflow-editing.md](workflow-editing.md) for the full frontmatter-vs-body recompilation taxonomy and the field list that requires `gh aw compile <workflow-id>` plus a `.lock.yml` review.