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

With no annotations, the description carries the full load and does a good job: it discloses the required sites:read scope and, notably, that a site outside the key's allowed site_ids is reported as not found rather than as an authorization error. It stops short of describing the response shape (error vs null) or any rate/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?

Three tight clauses, no repetition, and the core action plus returned fields are front-loaded before the scope and error behavior. Every sentence earns its place.

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 one-parameter, no-output-schema tool, the description covers the auth requirement, the returned fields, and the not-found masking behavior. The only small gap is not clarifying whether the not-found case raises an error or yields an empty result.

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 site_id parameter is fully documented in the schema, including the ownership constraint. The description adds only the phrase 'by id', so the baseline 3 for schema-driven parameters applies.

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 ('Get one site by id') and immediately narrows scope by enumerating the returned fields. The word 'one' cleanly separates it from the sibling list_sites, so an agent can route between them without opening a schema.

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 is implied by the required id and the singleton framing, but the description never explicitly says when to prefer this over list_sites or get_run. No exclusions or alternatives are named, leaving the routing inference to the agent.

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