[codex] Preserve skill descriptions outside model context

[charlesgong-openai]

Why

Skill descriptions are used in model-visible lists: the default available-skills catalog that supports implicit selection, and the on-demand skills.list tool response used to discover orchestrator skills. A single overlong description should not consume a disproportionate share of either list.

Enforcing the 1024-character limit while loading or migrating skills is the wrong boundary: it rejects otherwise-valid skills and discards metadata that non-model consumers and full skill reads may need. Skill metadata and SKILL.md content should remain intact; the cap belongs at model-visible list rendering boundaries.

What changed

• Preserve full description and metadata.short-description values when loading skills.
• Preserve full external-agent command descriptions during source-command-* migration instead of skipping commands solely because their descriptions exceed 1024 characters.
• Preserve full normalized orchestrator descriptions in the underlying skills catalog.
• Cap each description at 1024 Unicode characters when rendering the default available-skills context in codex-core-skills and codex-skills-extension.
• Apply the same cap when serializing descriptions in the model-visible skills.list response.
• Render truncated descriptions as 1021 original characters plus ....
• Leave explicit $skill injection, skills.read, underlying metadata, and on-disk SKILL.md files unchanged and full-fidelity.

Implicit skill selection

Codex injects a bounded catalog containing each implicitly allowed skill's name, description, and source locator, together with instructions to use a skill when the task clearly matches its description. The model makes that semantic choice; after selecting a skill, it reads the full SKILL.md from its filesystem or provider resource. Explicit $skill mentions remain a separate path that injects the full skill instructions. For orchestrator skills, skills.list provides bounded discovery metadata before skills.read returns the full selected resource.

Test plan

• just test -p codex-core-skills
• just test -p codex-skills-extension
• just test -p codex-external-agent-migration

The focused regressions verify that overlong metadata is preserved at load and migration boundaries while default available-skills rendering and skills.list output produce the 1021-character prefix plus ....

[chatgpt-codex-connector]

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