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

Annotations are present (readOnlyHint:false, idempotentHint:false, destructiveHint:false), and the description adds substantial behavioral context beyond them. It discloses the payment flow (250-sat L402 settlement, no second HTTP payment), validation of Bitcoin tip and signing readiness, rate limits (60 req/min shared across /mcp), and error conditions (402, 429, 503, -32602). No contradiction with annotations.

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 structured with labeled sections (PURPOSE, USAGE, PARAMETERS, BEHAVIOR, RETURNS, ERRORS) that front-load purpose and make scanning easy. Length is justified by the tool's complexity (payment, verification, multiple error modes). No redundant sentences; each section adds necessary information.

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?

Despite having an output schema, the description still summarizes the return object's fields and gives a verification endpoint, which is useful. It also covers parameter validation and error handling, making the tool safe to invoke without external documentation. The addition of rate limits and settlement details completes the invocation context.

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 each parameter is already documented in the schema with details like the pattern, min/max lengths, and normalization. The description simply repeats these facts in the PARAMETERS section without adding new semantic meaning, so the baseline of 3 is appropriate.

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 opens with 'Creates a signed epistemic anchor receipt for agent context grounded in the current Bitcoin tip', which states a specific verb, resource, and scope. It also explicitly distinguishes this tool from proof.verify by naming the alternative for raw ZK proof verification, allowing an agent to select it correctly without opening schemas.

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 USAGE section states 'Use to ground agent context and obtain a verifiable receipt' and explicitly says 'Do NOT use for raw ZK proof verification; use proof.verify instead.' This provides clear when-to-use and when-not-to-use guidance with the specific alternative. No ambiguity remains about which sibling to choose.

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