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

With no annotations, the description carries the full burden and partially meets it: it discloses the output shape (quotes, XBRL changes, riskDelta), the payload-size tradeoff via compact, and a hard cost of $0.05. It says nothing about permissions, latency, rate limits, or error behavior, and the phantom 'mode'/'compact' flags muddy the contract. Partial but useful disclosure.

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?

Front-loaded with the value statement, then use hints, then savings and cost, in four compact sentences with no filler. Slightly weakened by the stray references to non-existent flags, but overall well-sized for the tool's complexity.

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?

For a 3-parameter tool with no output schema, describing the return content is genuinely valuable and largely done here, and cost is disclosed. But the description references parameters that do not exist, which undermines confidence that it accurately describes this tool's interface. Adequate but with a real accuracy gap.

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%, so the real parameters (ticker, filingType, question) are already documented and the baseline would be 3. However the description references 'mode=diff' and 'compact=true', neither of which exists in the input schema, actively misinforming the agent about the callable interface. This is worse than adding no parameter info.

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: it diffs risk factors between the latest and prior 10-K/10-Q, returning added/removed/changed items, XBRL changes and a riskDelta summary. This is concrete enough to distinguish it from generic siblings like sec_analyst or search_13f_whale_filings. An agent knows exactly what it produces without opening the 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?

Implies the usage context ('saves reading two full risk sections, often 60k+ characters') and gives a value proposition, but never names when NOT to use it or which sibling (e.g. sec_analyst) to prefer. It also instructs 'Use mode=diff', which is confusing since no such mode selection is framed as a decision. Guidance is present but incomplete.

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