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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the burden is lighter. The description still adds genuinely necessary context the annotations cannot express: a per-call cost of 0.01 USDC via x402 PAYMENT-SIGNATURE or free with an API key, which changes how a client must invoke it. It stops short of describing ranking/scoring behavior or failure modes.

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?

Two sentences, front-loaded with the purpose and followed by the payment/access constraint. No filler, though the bracketed access note is dense and could be split for readability.

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?

With no output schema, the description should convey what 'ranked signals' actually returns (identifiers? similarity scores? full signal definitions?) and how ranking is ordered. It also leaves the role of user_intent, a nested object, unexplained. Adequate to call it correctly, not adequate to predict its response.

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 all six parameters (including the enum-constrained role and the user_intent nested object) are documented in the schema itself; baseline 3 applies. The description contributes nothing about how top_k, similarity_threshold, or user_intent affect the match, but it is not required to given full coverage.

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 first sentence gives a specific verb ('Match') and resource ('trading description' -> 'ranked signals'), so the operation is clear. However, it does nothing to separate itself from close siblings such as search_signals, list_signals, or query_signal_behavior, which an agent will have to disambiguate on its own.

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?

There is no guidance on when to call this rather than search_signals or query_signal_behavior, no stated prerequisites, and no exclusions. The intent (semantic matching of a natural-language rule description) is only implied by the verb 'Match'.

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