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

With no annotations, the description carries the full burden and does substantial work: it discloses the not-found behavior for unknown slugs, that figures may be provisional, that permit status is one of three enumerated values or null when unrecorded, that null means 'not recorded', and that figures should be verified via get_provenance. It stops short of auth requirements, rate limits, or caching behavior.

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?

Front-loaded with the resource and its contents, then the error case, then semantics. It is somewhat choppy in its many short declaratives and spends several sentences on citation/null policy, but each sentence carries distinct information rather than filler.

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?

With no output schema and no annotations, the description compensates well by naming the record's key fields (permits, provenance, geometryUrl) and interpreting the permit-status values and null semantics. For a single-parameter read tool this is nearly complete; only the remaining record fields and any auth/pagination notes are unaddressed.

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 coverage is 100% and the single slug parameter is fully documented in the schema with an example, so the baseline is 3. The description only adds the negative case ('Unknown slug returns not found'), which is behavior rather than parameter meaning, so it does not exceed the baseline.

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?

States a specific verb and resource ('Full sourced trail record from /api/v1/trails/{slug}') and enumerates what the record contains (permits, provenance, geometryUrl), so an agent knows exactly what it gets. It does not explicitly draw the boundary against siblings like get_permit or get_geojson, which it could have done to prevent overlap confusion.

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?

Usage context is implied rather than stated: it reveals the error case ('Unknown slug returns not found') and a follow-up path ('can be verified with get_provenance'), which guides the agent. There is no explicit when-to-use-this-vs-search_trails or prerequisite statement, so the guidance is adequate but incomplete.

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