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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds operational context beyond the hints, such as 'performs one internal daily-changes read, filters evidence for one issuer/change' and pagination behavior. It aligns with annotations and provides useful extra detail, though not extensive.

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 four sentences with a clear structure: purpose, returns, parameters, behavior/exclusions. It is front-loaded with the primary use case, contains no redundant filler, and every sentence contributes distinct information.

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?

The description covers purpose, usage guidelines, parameter semantics, behavior, and exclusions. Since an output schema exists, return structure is not needed, but it still mentions 'page metadata and issuer identity'. The explicit exclusions address sibling-tool overlap, making it self-sufficient for a drilldown tool.

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% and schema descriptions are already detailed (e.g., limit default/max, source_date format). The description adds the requiredness constraint 'ticker or cik is required' (not enforced in schema) and clarifies that 'offset paginates the raw tag page', which adds meaning beyond the schema definitions.

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 clearly identifies the tool as a 'read-only drilldown tool' that 'returns paginated raw CompanyFacts tag evidence for a specific ticker or CIK'. It scopes the purpose to 'why one issuer or CIK was flagged in daily changes', which distinguishes it from broader monitoring or Alpha Sweep tools among the siblings.

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 when to use: 'only when the user asks why one issuer or CIK was flagged in daily changes', and provides exclusions: 'Do not use it for routine monitoring, Morning Brief, or Alpha Sweep unless the user explicitly asks for proof.' This names alternatives and gives clear when-not guidance.

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