Reject empty agent slugs before cleaning conversion output

[rudycelekli]

What does this PR do?

Implements the maintainer-approved item 2 in #917. A nonempty Unicode-only name can normalize to an empty ASCII slug. Reject it in lint and converter preflight before cleaning output; retain the Unicode display name when an explicit ASCII alias is supplied. No transliteration.

Coordination: #917 candidate list. Empty-slug scope is separately approved in the maintainer’s preceding comment.

Agent Information (if adding/modifying an agent)

• Agent Name: Agent validation and conversion
• Category: Tooling (approved existing scripts)
• Specialty: Installer/discovery metadata

Verification

Original accepts an empty slug. Fixed native fixture rejects it before touching a pre-existing sentinel; explicit “Expert 专家” and plain ASCII names convert. Existing regression now checks the sentinel and valid alias. Bash 3.2 syntax, tools/divisions, collision, folded/closing frontmatter and complete three-tool frontmatter regressions passed.

• Independent review of the complete frozen patch and native controls passed.
• Scoped lint/originality and git diff --check passed for content; focused script regressions above passed for tooling.
• On one combined snapshot of the 14 disjoint content patches plus the approved empty-slug fix: full-roster lint passed (282 agents, 0 errors, 58 existing warnings); originality passed; converter round-trip/strict-parse/count checks passed (32 checks, 0 failures, 282 agents × 15 tools). Exactly 14 expected agent checksum drifts are advisory; no checksum/generated files are committed. Full installer suite: 66 passed, 0 failed, 2 documented expected failures for fix(installer): preserve paths with spaces in parallel mode #755. This full suite ran on the combined snapshot, not independently on each PR.

Limits

ASCII aliases are supplied by the author; no locale-dependent normalization or automatic transliteration is introduced.

Checklist

• Preserves the existing agent template/persona (tooling scope is separately approved).
• Existing YAML metadata is preserved.
• Includes a concrete reproduction and focused scenario controls.
• Reviewed/proofread; no generated integration files or checksum changes.

CI fixture correction

The first Linux run caught an obsolete Codex SKILL-path expectation in the new alias fixture. The current converter correctly emits codex/agents/expert.toml. The fixture now checks that path and explicitly exits on either a missing artifact or a changed preservation sentinel, including on Bash 3.2. The complete frontmatter suite passed on the unchanged final script hash; an independent actual-fixture replay also confirmed healthy success and both forced-failure diagnostics. Production linter/converter code is unchanged by this follow-up. Fresh upstream checks are pending.

[phant0um]

I tested this PR on macOS 27 with bash 5. Setup: main at 8329468, and main with this PR merged on top (64319d2). The merge is clean.

For the plant, I copied engineering/engineering-ai-data-remediation-engineer.md to engineering/zz-probe.md in a temp copy of the repo. Then I changed only the name: line. Each case ran 2 times with the same result.

Case	main	main + PR
name: 专家, lint-agents.sh	exit 0, no message	exit 1, produces an empty agent slug
name: 专家, convert.sh --tool codex	exit 0, writes codex/agents/.toml	exit 1, empty agent slug for engineering/zz-probe.md, old output kept
name: ---	same as 专家	same as 专家
name: Expert 专家	exit 0, writes expert.toml	exit 0, writes expert.toml

On main the bug is silent. In one full convert.sh run with name: 专家, the script exits 0 and writes hidden files with an empty stem in 8 places: codex/agents/.toml, cursor/rules/.mdc, gemini-cli/agents/.md, opencode/agents/.md, qwen/agents/.md, vibe/agents/.toml, vibe/prompts/.md and zcode/agents/.md. ls does not show these files. The PR stops this before clean_tool_output runs, so existing output stays in place.

The new block in test-convert-frontmatter.sh passes on the PR. With the scripts from main, it fails on the first new assertion: Expected linter to reject an agent name with an empty install slug. The test catches the bug.

Not tested: the converter with the PR for tools other than codex. I did not run it because check_agent_slug_collisions runs once, before the tool loop. I also did not check hermes/.../agents.json or shellcheck.

Command I used per case:

sed 's/^name:.*/name: 专家/' engineering/engineering-ai-data-remediation-engineer.md > engineering/zz-probe.md
scripts/lint-agents.sh engineering/zz-probe.md; echo "lint=$?"
scripts/convert.sh --tool codex --out /tmp/out; echo "convert=$?"