gc_project_registry

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It discloses meaningful behavioral traits: upsert 'supports partial payloads' and 'metadata is merged', and sync pulls 'from ~/.config/gc/registry.toml into the registry DB'. These reveal merge semantics and the sync source path, which is valuable behavioral transparency for an otherwise 24-parameter tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is efficiently structured with a leading summary line followed by a bulleted action list and a closing guidance sentence. It's front-loaded and wastes no words. Minor deduction: the action list overlaps with the schema's enum which is already self-documenting, though the brief per-action glosses do add value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 24-parameter tool with no output schema and no annotations, the description does a solid job: it enumerates actions, highlights merge semantics for upsert, and explains the sync source. However, it doesn't describe the return format for list/get/repos actions, what happens on sync conflicts or failure, or destructive implications (e.g., does upsert overwrite all fields or only provided ones?). Slight gaps given the tool's complexity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema thoroughly documents all 24 parameters. The description adds a small amount of extra meaning (upsert supports partial payloads with merged metadata), but otherwise the semantics are carried by the schema. At this coverage level, baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it's the 'Canonical project registry for Grand Central' and enumerates five concrete actions (list, get, upsert, sync, repos) with specific semantics. It also distinguishes itself from alternatives by stating it should be the 'source of truth' for project metadata and to 'prefer over maintaining sidecar maps'. This is a specific verb+resource tool with clear action enumeration.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear guidance to use this as the source of truth for project metadata (repo paths, canonical docs, related projects, strategy-sync metadata) and explicitly says to prefer it over sidecar maps. However, it doesn't explicitly name sibling tools to use instead, only generically references 'maintaining sidecar maps' and doesn't state when NOT to use it in favor of specific alternatives among the many gc_* siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.