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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive, openWorldHint=false), so the bar is lower. The description adds real interpretation context beyond them: it explains that a null score means no tracked mentions in that window rather than a low score, which prevents a likely agent misreading, and 'signed-in user's' implies authentication is required. It does not mention result ordering, size, or empty-watchlist behavior.

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 verb and scope, then the payload shape, then the one non-obvious edge case. No filler or restatement of the title.

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?

There is no output schema, so the description carries the burden of describing return values, and it does so at a useful level: one entry per company with 24h and 7d scores and a tier word, plus null semantics. Minor gaps remain around the list container, ordering, and what an empty watchlist returns, but nothing that would cause a wrong call.

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 there is nothing for the description to disambiguate; baseline 4 applies. The description correctly adds no parameter chatter.

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 ('Returns the signed-in user's own watchlist') and scopes it to the authenticated user, which separates it from company-level siblings like get_company_score or get_company_signals. It also names the per-company payload (24h and 7d signal score plus tier word) so the agent knows what the resource contains before calling.

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?

Usage is implied rather than stated: the 'signed-in user's own' phrasing implies this is the personal watchlist call rather than a company lookup, and the zero-parameter schema makes self-selection easy. There is no explicit when-to-use/when-not-to-use guidance or named alternative for fetching scores of companies not on the watchlist.

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