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

The readOnlyHint annotation already establishes that this is a safe, non-mutating read, so the description carries a lighter burden. It adds the underlying endpoint (Census: GET /sources/{id}), which confirms the operation maps to a single-resource fetch, but it says nothing about not-found behavior, permissions, or rate limits. Adequate but thin for a read 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?

Two short sentences, zero filler, with the operation front-loaded before the endpoint reference. Nothing is padded or redundant.

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 simple single-resource read with no output schema, a 100%-covered schema, and a readOnlyHint annotation, the description supplies everything needed to invoke the call correctly. Only minor gaps remain, such as error/not-found behavior, which an agent might reasonably want.

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% with a single required 'id' string parameter fully documented as a numeric id passed as a string. The description restates 'by id' without adding format, scoping, or validation guidance beyond the schema, so the baseline of 3 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?

The description states a specific verb (Get) and resource (a single source connection) and scopes it to retrieval by id, so an agent can distinguish it from census_list_sources or census_get_destination. It is clear and precise, though it never explicitly names a sibling as the alternative, which keeps it out of the top band.

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 phrase 'by id' weakly implies the tool is for when a source id is already known, but there is no explicit when-to-use statement, no contrast with census_list_sources for discovery, and no note on what to do if the id is unknown. Usage must be inferred.

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