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

Annotations already declare this a read-only, idempotent, non-destructive operation, so safety profile needs no restating. The description adds real context beyond that: it reads the watch's last read plus daily snapshots rather than a live job board, and it implies the results can be stale until watch_new_roles is called.

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 'Best for / Returns / Input tips / Not for' structure puts the routing decision first and leaves no filler. The 'Input tips' line is mostly redundant with the schema and could be dropped, which keeps it short of perfect.

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?

An output schema exists, so return values need no explanation, and the description covers the freshness caveat and the sibling routing decision. The only gap is that it never says the watch_key comes from a prior call, though the schema field description does.

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% for the single watch_key parameter, so the schema already carries the meaning and the baseline is 3. The 'Input tips' line only restates the key format already given by the schema pattern, so it adds little beyond the structured field.

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 gives a specific purpose (ranking watched companies by hiring speed) and verb-level output detail ('open roles and roles opened and closed over 7 and 30 days, fastest first'). It also distinguishes itself from the sibling watch_new_roles, which an agent could otherwise mistake for it.

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 explicitly states the question it answers ('who on my watch is hiring most this week?'), names a prerequisite call ('call watch_new_roles first for fresh counts'), and gives an explicit exclusion ('Not for: starting a watch'). Both when-to-use and when-not-to-use are covered.

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