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

readOnlyHint=true already declares this is a safe read, so the annotation carries the safety profile. The description adds the returned field set, which is useful, but says nothing about error behavior for an invalid jnid, pagination, rate limits, or auth needs — modest added value against an annotation baseline.

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 tight sentences, front-loaded with the fetch action and its returned payload. Every clause earns its place, with the endpoint reference appended last.

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 single-parameter read tool with no output schema, listing the returned fields is a genuinely useful stand-in for the absent return spec. Only minor gaps remain (invalid-jnid behavior), and annotations cover the read semantics.

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% and the single jnid parameter is documented there, so baseline is 3. The description restates that the job is fetched by jnid but adds no format, sourcing, or lookup guidance beyond the schema.

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 (Fetch) and resource (a single job by jnid) and enumerates the returned fields. The word 'single' implicitly distinguishes it from list_jobs, but it does not name the sibling to make the contrast explicit.

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 only implied: 'single job by jnid' suggests a lookup when the jnid is already known, contrasting with the list_jobs/update_job siblings. There is no explicit when-to-use or when-not statement, and no mention of what to do when the jnid is unknown.

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