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

Annotations already cover the read-only, idempotent, non-destructive, closed-world profile, and the description adds meaningful context beyond that: the paid segment-plan API key requirement and the subscription_required failure mode. It also discloses the return payload shape (boards, open roles, baseline average, ratio, spike flag, as_of, method) and the 50-row cap for function/city segments. Slightly held back from 5 only because rate limits or error modes beyond subscription_required are not mentioned.

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 uses labeled sections (Best for / Returns / Input tips / Needs / Not for) and leads with the strongest routing signal. Each sentence contributes either routing, semantics, or prerequisite information with no filler.

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?

Given an output schema exists, the description needn't detail return values, yet it summarizes them anyway, and it covers the cost/auth prerequisite, segment semantics, and the sibling alternative. Nothing an agent needs to invoke this correctly 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?

Schema coverage is 100%, so the parameter descriptions carry the basics, but the description adds real interpretive value: omitting segment ranks every company, function/city returns a this-week leaderboard capped at 50, and city/function must both match. The input-tip examples show valid segment shapes that go beyond the single schema example.

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 ('companies ranked by new roles over 7 days') and frames the use case with a concrete example question. It explicitly distinguishes itself from the sibling company_hiring_brief, so an agent can route without inspecting either 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?

It gives an explicit 'Best for' condition, a 'Not for' exclusion that names the alternative tool (company_hiring_brief), and clarifies that country and size are not valid filters. The when-to-use vs when-not-to-use split is fully spelled out.

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