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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds value beyond that: ids are stable ('they keep working later'), must be copied exactly, and NHS Jobs/Teaching Vacancies results carry a closing date. This is genuine behavioral context, not a restatement.

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 purpose in the first sentence and every subsequent sentence adds a distinct piece of information (triggers, id provenance, source-specific fields). The opening sentence duplicates the title, which is minor redundancy but not bloat.

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, the description carries some burden for return values; it discloses one source-specific field (closing date) but not the general shape of a job detail. For a single-parameter lookup tool with full annotation coverage, this is nearly complete, with only minor gaps in return-value description.

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 id format is already documented, giving a baseline of 3. The description adds meaning beyond the schema by stating the id must come from a search_jobs result and that ids remain valid later, clarifying provenance and persistence.

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 ('Details for one job from a search result') and scopes it to a single result, distinguishing it from the sibling jobspotter_search_jobs. An agent can tell it is a detail-fetch, not a search, without opening any 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?

Explicitly says when to use it ('For when the user asks about one of the results') and provides two concrete trigger examples. It also routes the agent to the source of the id (a search_jobs result). It stops short of naming a when-not condition, but for a pure detail-fetcher this is clear context.

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