fix(fullsend): add safe-retry skill to prevent fix agent retry loops

.fullsend/customized/harness/fix.yaml

@@ -17,6 +17,7 @@
 #   - host_files: rhdh-toolchain.env sets COREPACK_HOME to writable /tmp/corepack
 #   - host_files: yarn-proxy.env maps OpenShell's HTTP_PROXY to YARN_HTTP_PROXY
 #   - skills: adds monorepo-workspace-routing for workspace navigation
+#   - skills: adds safe-retry to guard against infinite retry loops
 #   - policy: custom fix policy with yarn registry + pnpm binary allowlist
 agent: agents/fix.md
 doc: docs/agents/fix.md
@@ -54,6 +55,7 @@ host_files:
 skills:
   - skills/fix-review
   - skills/monorepo-workspace-routing
+  - skills/safe-retry
 
 runner_env:
   PUSH_TOKEN: "${PUSH_TOKEN}"

.fullsend/customized/skills/safe-retry/SKILL.md

@@ -0,0 +1,52 @@
+---
+name: safe-retry
+description: >-
+  Guards against infinite retry loops when the agent introduces syntax or
+  parse errors during edits. Requires diagnosis before retrying any failing
+  command and enforces hard stop thresholds.
+---
+
+# Safe Retry
+
+When a test, build, or lint command fails after you edited code, the error
+is most likely YOUR fault — not a pre-existing issue or a flaky test. Before
+retrying any failing command, you MUST follow the diagnosis steps below.
+
+**This skill overrides any instinct to "just retry."**
+
+## Diagnosis before retry
+
+After every test/build/lint failure:
+
+1. **Read the full error output.** Identify the failing file and line number.
+2. **Check if the failing file is one you edited.** If yes, the error is
+   self-inflicted. Fix the file first — do not retry the command.
+3. **Classify the error.** Syntax errors, parse errors, unexpected token
+   errors, and import/export resolution errors are almost always caused by
+   incomplete edits (e.g., renaming a symbol in one place but not updating
+   its import, or breaking a multi-line statement).
+
+## Hard rules
+
+- **Never retry the same command without changing code first.** If a command
+  failed, running it again without edits will produce the same failure. This
+  includes variations like `yarn test`, `yarn backstage-cli package test`,
+  and `yarn backstage-cli package test --no-cache` — these are the same
+  command with different flags, not different fixes.
+- **After 2 consecutive test failures, STOP and diagnose.** Re-read every
+  file you edited. Diff your changes against the original. Look for broken
+  imports, unclosed brackets, missing commas, and partial renames. Fix the
+  root cause before running tests again.
+- **After 3 total test failures across the entire run, produce structured
+  output with `tests_passed: false` and stop.** Do not commit broken code.
+  The post-script will report the failure and a human can intervene.
+
+## Common self-inflicted errors
+
+| Error pattern                                   | Likely cause                                       | Fix                                                 |
+| ----------------------------------------------- | -------------------------------------------------- | --------------------------------------------------- |
+| `SyntaxError: Unexpected token`                 | Incomplete edit broke the AST                      | Read the file around the error line; fix the syntax |
+| `Unexpected token, expected "from"`             | Broke an `import` statement (e.g., partial rename) | Check all `import`/`export` lines in the file       |
+| `Module '"./foo"' has no exported member 'Bar'` | Renamed an export but didn't update imports        | Find all files importing `Bar` and update them      |
+| `Cannot find module './foo'`                    | Renamed or moved a file but didn't update imports  | Grep for the old path and fix references            |
+| `TypeError: X is not a function`                | Changed a function signature or export             | Check callers                                       |