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

With no annotations, the description carries the full burden, and it does disclose something valuable and non-obvious: a 0.005 USDC x402 payment or API-key auth, with auto-pay behavior for x402 clients. It says nothing about read-only semantics, cost of computation, latency, or result caching for what appears to be a scanning/aggregation query over 14 parameters.

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 short components: the mode enumeration front-loaded, then a bracketed access note. No filler, and the payment constraint — the most surprising thing an agent needs — is called out explicitly rather than buried.

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?

The auth/payment disclosure is a real contribution given zero annotations, and the schema fully covers params. But for a 14-parameter, four-mode tool with no output schema, the description gives no hint of return shape and no help choosing a mode, leaving the agent to reconstruct the mode contract entirely from the schema.

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 each parameter's meaning, mode applicability, and units are already documented in the schema, including the mode-specific enumerations. The description adds nothing beyond repeating the four mode names, so baseline 3 applies.

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 ('Query') and resource ('measured signal behaviour') and enumerates the four modes. However, the mode names (describe, pick, find, gap_probability) are opaque without opening the schema, and nothing distinguishes this from siblings like evaluate_signal, get_signal, or search_signals.

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?

No guidance on when to choose this over evaluate_signal, get_signal, list_signals, or search_signals, which all touch the same signal domain. The only positional hints ('pick', 'find') are mode names, not usage conditions, and no exclusions or prerequisites are stated.

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