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

Annotations already cover read-only, idempotent, and non-destructive traits. The description adds valuable behavioral context beyond annotations: it explains the meaning of coverage_status 'no_ats_signal' (not evidence of quietness), the signup-link response when no API key is passed, and the ATS/board-only freshness floor. This is meaningful extra disclosure without contradicting annotations.

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?

The description is a dense single paragraph, but every sentence adds necessary detail—usage context, parameter constraints, example outputs, and the sibling alternative. It is front-loaded with the primary usage scenario. Slightly longer than minimal, but no wasted words.

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 tool with no output schema, the description provides concrete output examples (is_hiring, open_req_count, coverage_status) and explains the critical nuance of the 'no_ats_signal' status. It also covers authentication fallback and the routing to the correct sibling. While it doesn't enumerate the full return structure, the examples and caveats are sufficient for correct invocation.

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 only 33%, but the description compensates well for `company_id` (must be an integer from an earlier result, not a name/domain) and `plane_api_key` (pass empty string to get signup link). It does not elaborate on `idempotency_key`, but this is a standard parameter and the description's targeted coverage outweighs the gap.

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 and resource ('is hiring' for a company), clarifies it takes a company_id (not name/domain), and distinguishes itself from the sibling `who_is_hiring_for` by noting it is for qualifying an already-known company. The examples further pin down the exact behavior, leaving no ambiguity.

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 description explicitly frames the tool as a 'cheap gate before spending a richer call' and provides a clear condition: use when the agent already holds a company and needs to qualify it. It also names the alternative `who_is_hiring_for` for finding companies, giving an explicit when-not-to-use. No exclusions are left implicit.

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