Conciseness

The body never explains concepts Claude already knows; it assumes full codebase competence ("useWorkspaceAppLayout", "tierWorkspaceApps", "filterBuiltInApps", "list-connected-agents") and spends every bullet on a project-specific constraint, matching the 'lean and efficient; every token earns its place' anchor. It is not a 4 because there is no over-explanation to trim — density here encodes real rules, not padding.

Actionability

Guidance is concrete and executable in instruction form: named APIs ("Dispatch uses list-workspace-apps and create_embed_session"), named stores and state keys ("application_state `chat-first-app-layout`"), and exact wiring instructions ("pass the rail its `togglePinned` as `onTogglePinned`"). It is below 5 only because there are no copy-paste-ready code examples for items like the shared open-app event or the origin/base-path allow-list; it is well above 3 since key details are specific rather than pseudocode-level.

Workflow Clarity

The Verification section is an explicit validation checklist ("Test the disabled path and the enabled path separately... verify rail ordering, chat history, app selection, embed-session errors, pane close") and error paths include recovery loops ("an unreadable read keeps changes on the device, shows the one Layout-level notice, and retries"), giving most checkpoints. It is not a 5 because the skill is a set of behavioral invariants rather than a clearly sequenced multi-step workflow, though the simple-skill exception keeps it above 3.

Progressive Disclosure

The body is well-organized into four clear sections (Contract, Client behavior, Agent and state boundaries, Verification), is self-contained, and makes no buried or nested references — no bundle files exist to reference. It misses a 5 because at ~64 lines with dense platform-specific rules (e.g. the long Dispatch `sections` and pin-store bullets) some content could arguably be split into per-platform reference files, though the current split is reasonable.

Specificity

"Implement or extend the opt-in Codex/T3-like chat-first shell" names the action and domain, and the trigger list names several concrete surfaces ("chat rails, contextual app panes, app opening, or local/mobile shell preferences") across named platforms ("Electron, Dispatch, or mobile"), matching the 'several specific actions; minor gaps' anchor. It is not a 3 because it covers more than 1-2 concrete change areas, and not a 5 because the verbs themselves (implement/extend/change) are fewer and less comprehensive than the top anchor's action coverage.

Completeness

The description explicitly answers both questions: the what is "Implement or extend the opt-in Codex/T3-like chat-first shell" and the when is an explicit "Use when changing chat rails, contextual app panes, app opening, or local/mobile shell preferences across Electron, Dispatch, or mobile" clause with concrete trigger phrases. This matches the top anchor exactly; a 4 would require the when to be less explicit or specific, which it is not.

Trigger Term Quality

Terms like "chat rails", "contextual app panes", "app opening", "shell preferences", "Electron", "Dispatch" are the natural vocabulary a developer on this codebase would use when asking for this skill, giving good keyword coverage. It falls short of a 5 because common synonyms and related terms (e.g. "app shelf", "workspace apps", "pins/pinning", "sections") are absent, but it is well above the 3 anchor's partial coverage.

Distinctiveness Conflict Risk

It carves out a clear niche — this app's opt-in chat-first shell work across specific surfaces and platforms — with distinct trigger terms, so the risk of it firing for an unrelated skill is minimal. It clearly fits the 'clear niche with distinct triggers' anchor rather than the 4 anchor's 'minor overlap risk with closely related skills'.