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

With no annotations, the description carries the full burden, and it discloses meaningful behavior: what is returned (each figure with evidence state), the comparability rules (a field neither records is not a tie, a field only one records is not a win), and that no per-field winner is declared because the published scoring model makes that judgement. It does not state read-only safety, auth needs, or error handling for invalid slugs.

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 lead sentence is short and front-loaded, but the remainder is a dense, clause-heavy run-on that mixes three separate ideas (comparability rules, tie/win semantics, model-sourced verdicts). The tie/win rule earns its place, but the phrasing is over-explained and could be trimmed.

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 must describe returns, and it does cover the shape of the response (figures, evidence state, grade) and comparability semantics. However it omits error behavior for invalid or unknown slugs and any indication of output format, leaving gaps for a tool with no structured return documentation.

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% and both parameters (a, b) are documented as firm slugs in the schema. The description adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 opening 'Two firms side by side' states the resource and the comparative operation clearly, and the following text specifies that each figure is reported with its evidence state and comparability. It distinguishes itself from single-firm siblings (get_firm, find_firms) by being a pairwise comparison, though the verb 'compare' is implied by the name rather than stated.

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?

There is no explicit when-to-use guidance and no reference to alternatives such as get_firm or list_firms. The agent must infer that this is for pairwise comparison rather than two separate lookups. The description explains output semantics but not selection context.

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