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

Annotations cover the safety profile (readOnly, non-destructive, closed-world), so the description's job is to add context — and it does: eight-quarter history depth, the SEC filing behind each period, pre-restatement values, and a permanent page address for citation. That is meaningful behavior beyond the annotations, though it says nothing about rate limits or response shape.

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: the first front-loads what is returned and its depth, the second routes to the sibling tool. Every clause earns its place with no repetition.

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?

With no output schema, the description carries the return-value burden and does so: it enumerates the filing linkage, prior/restated values, and permalink. For a two-parameter, annotated, read-only tool this is sufficient to call correctly.

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 both parameters are already documented, including the enum. The description restates the four metric options but adds no syntax or format detail (e.g., acceptable ticker vs. name handling beyond the schema's own example). Baseline 3 is correct when the schema does the heavy lifting.

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 one figure for one company over the last eight quarters — and enumerates the covered metrics. It explicitly distinguishes itself from get_financials, so an agent can route between the two without opening either schema.

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?

Gives an explicit when-to-use ('when the user wants a figure verified, cited or traced to its filings') and names the alternative with the condition that selects it (every statement line over 12 quarters / 6 fiscal years → get_financials). Nothing is left to inference.

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