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

Annotations already provide read-only, idempotent, and non-destructive signals, so the description adds useful context by promising explicit source timestamps, coverage, and expiry. This helps an agent understand freshness and scope beyond the annotation booleans. It does not disclose unknown-ticker failure behavior, but that is not critical given the schema and output schema.

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 two sentences with the core use case front-loaded and exclusions placed after. There is no repetition of schema details and no filler; every sentence contributes decision-useful 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?

Given the rich schema, enums, output schema, and annotations, the description provides the essential decision context without duplicating structured data. It covers what the tool is for, what it returns, and what it is not for, which is sufficient for correct selection and invocation.

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 88%, and the parameters already carry detailed descriptions for view, max_age, history_days, changed_since, desired_fields, compare_sources, and max_age_seconds. The description adds no parameter-level semantic guidance beyond 'known ticker,' but with high schema coverage, baseline 3 is appropriate.

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 purpose: 'Use for current SEC filing-event state for a known ticker' and names concrete outputs such as issuer/CIK, filing dates, and source links. It also distinguishes itself by explicitly excluding financial-statement extraction, earnings transcripts, and broad equity research.

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 a clear when-to-use trigger ('Use for current SEC filing-event state for a known ticker') and explicit non-goals ('Not financial-statement extraction, earnings transcripts or broad equity research'). It does not name a specific alternative tool to route to, but the exclusions are concrete enough to guide selection.

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