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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuine extra context — that output includes live counts and that the call is cheap — which helps an agent decide to call it proactively. No auth or rate-limit detail, but none is needed here.

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 sentences, front-loaded with the when-to-use condition, followed by the return shape and a cost hint. Every clause carries information; nothing is padding.

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 zero-parameter, read-only lookup with no output schema, the description covers the three things an agent needs: when to call it, what it returns, and that it is inexpensive. Nothing material is missing.

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?

The tool takes zero parameters, so per the baseline this scores 4; the empty schema matches the description's implicit claim that no arguments are needed. Nothing in the description contradicts or complicates the empty input contract.

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 ('list_sectors' → the valid sector, seniority, job type and posted-date values) and explicitly ties it to search_jobs, so it is clearly distinguishable from get_job and search_jobs. The return content (four sectors with scope and live open-job counts) is named up front.

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?

Gives two explicit triggering conditions: needing valid filter values for search_jobs, or a user asking what kinds of energy jobs exist. It names the sibling it feeds, so the agent knows this is a lookup step before search_jobs rather than a replacement.

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