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

readOnlyHint=true already tells the agent this is a safe read, so the description's added value is limited to characterizing the operation as a broad universe scan rather than a targeted lookup. It does not mention default sort/limit behavior, result volume, or the paid-key gating visible only in the schema, so it adds some but not rich behavioral context.

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 tightly written sentences, front-loaded with the core action and immediately followed by the routing rule. Every clause earns its place with no 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 9-parameter, 0-required filter tool with full schema coverage and no output schema, the description covers what it does and when to prefer a sibling. It is slightly thin on return-shape expectations (row volume, ticker+score payload) but nothing essential for correct invocation 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 description coverage is 100%, including enum meanings and the paid-key caveats on house_rating_confidence and rating, so the baseline is 3. The description contributes no parameter-level detail (e.g., limit semantics or interaction between sort/order) beyond what the schema already provides.

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+resource+scope: 'Filter the whole equity universe and return matching tickers with their scores.' It also names the sibling it is not (rank_consensus for cross-signal ranking), so an agent can distinguish it from the get_* and list_* siblings without opening schemas.

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?

Explicitly labels itself 'the bulk discovery tool' and gives the triggering question shape ('which companies have X'), plus a concrete alternative and the condition that selects it ('To rank by cross-signal agreement instead, use rank_consensus'). This is exactly when/when-not/alternative guidance.

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