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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful context: a 0.10 USD fast specialist operation when runtime commerce is active, deterministic pair selection, and a clear disclaimer that this is not a legal materiality determination. This goes beyond what annotations alone provide.

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 and front-loads the operation and cost context. It is efficient, but the cost/runtime-commerce sentence is somewhat tangential and could be clearer or placed elsewhere. Overall, it earns its place without being bloated.

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 output schema exists, the description does not need to explain return values. It covers the operation, pair selection, scope limitations, and output categories. It is complete enough for an agent to invoke correctly, though explicit sibling differentiation would improve selection confidence.

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%, so the baseline is 3. The description adds meaningful parameter semantics by explaining the exact-pair accession requirement and the alternative of omitting both accessions to let the tool deterministically select the latest comparable pair. This is beyond what the schema states.

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 states the tool compares two same-form 10-K or 10-Q filings and returns meaningful changes, with a specific verb and resource. It does not explicitly distinguish itself from sibling tools like compare_filings or check_disclosure_changes, so it falls short of a 5.

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?

The description gives concrete usage instructions: supply both accessions for an exact pair, or omit both and let FiledProof select the latest comparable pair. It also notes this is not a legal materiality or investment-significance determination, but it does not name alternatives or explicitly state when to prefer this tool over siblings.

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