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

The description goes well beyond the annotations, disclosing that the tool is free, that it answers with available:false while unavailable, that it is not charged in that state, that it rejects portfolio/position/risk-profile inputs with HTTP 400, and that payment requires x402 over Base Sepolia. This is substantial behavioral context beyond readOnlyHint.

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 information-dense and mostly well structured, but it contains redundancy: 'FREE' and 'is NOT charged while that is true' repeat the same point, and 'NOT YET AVAILABLE' appears twice. The sentence 'Commentary on public statements, not advice' also appears unrelated to tool invocation and adds noise.

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 two-parameter tool with no output schema, the description is remarkably complete. It covers availability, response behavior, charging, error conditions, and the payment interaction flow. An agent has enough context to call the tool correctly and interpret the expected outcome.

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 value by explaining the payment parameter in detail: the X-PAYMENT header mapping, base64 encoding, the initial call to receive 402 terms, and settlement on Base Sepolia. This exceeds what the schema alone provides.

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's purpose: emit the whole board as it stood on a past date with that day's anchor proof. It also contrasts this with the current board, which helps distinguish it from the sibling latest_board without opening any 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?

The description explicitly says the feature is not yet available, that only the current board is emitted, and that the tool will return available:false without charging. It also gives a clear two-step payment flow. It could be stronger by explicitly naming latest_board as the alternative for current data, but the context makes the intended usage reasonably clear.

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