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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety and mutability. The description adds valuable context: it specifies the cost structure ($0.10 USDC via x402, with a free first cached result) and reiterates that it is not a recommendation. It also mentions the 'guarded' nature, though not fully explained. No contradiction with annotations; the description enhances behavioral understanding.

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 three sentences with no fluff. It front-loads the core purpose, then adds constraints (filing scanner only, not a recommendation) and cost details. Every sentence earns its place, and the structure is clear and efficient.

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 read-only tool with no output schema, the description covers the essential operational details: what it reads, that it is not advice, the cost model, and the payment mechanism. It does not explicitly describe the return format, but given the name 'brief' and the nature of the tool, this is likely understood. The absence of an output schema is mitigated by the description's clarity, though a mention of the result format would make it more complete.

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 both parameters (ticker and x_payment) are fully described in the schema. The description does not add any new parameter-specific meaning beyond what the schema already provides, such as the payment challenge flow or ticker format. With full schema coverage, the baseline of 3 is appropriate; the description adds no extra semantic value.

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 verb ('Read'), a resource ('guarded AI brief over observed SEC Form 4 flow, 13D/13G ownership events, and fundamentals'), and a target ('US ticker'). It clearly conveys the tool's function and hints at differentiation by noting 'Filing scanner only' and that it does not give buy/sell advice, distinguishing it from advisory tools. However, it does not explicitly name sibling tools like otto_equity_smart_money, so it is clear but not maximally distinct.

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 implies usage context by stating it is a filing scanner and that it rejects buy/sell advice, suggesting it is for intelligence rather than recommendations. It also mentions the x402 payment flow. However, it does not explicitly state when to use this tool versus siblings like otto_equity_intel or otto_insider_trades, nor does it provide exclusions. Guidance is implied but not explicit.

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