402Signal

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

With no annotations, the description carries the full burden and does so well: it states preview does not probe, does not charge, and returns not_probed:true. It also names the output fields, making the behavior and side-effects visible to the agent.

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 four short sentences, each earning its place: operation, outputs, constraints, and the alternative for a live probe. It is front-loaded and contains no filler.

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 description is complete for this tool: it explains what it returns, what it does not do, and where to go for a live probe. The output schema covers return-value structure, so the text does not need to repeat it. Only the validate sibling is unaddressed, but that is a minor gap.

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 the schema already documents all three parameters, including semantics for networks vs prefer_network. The description adds no additional per-parameter detail, so the 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?

The description specifies a concrete operation: a request-time catalog preflight over upstream catalogs plus a local shadow. It also distinguishes itself from route by explicitly saying it does not probe and does not charge, though it does not address the validate sibling.

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?

It clearly tells agents when to use an alternative: 'Pay tools/call route for a live probe.' The description also implies preview is the correct choice when no probe and no charge are desired. It does not provide an exhaustive when-to-use list or mention validate as an alternative.

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

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

No annotations exist, so the description carries the full burden. It provides meaningful behavioral context beyond the schema: the check is live, evidence is shown, the agent keeps custody of the wallet, and decision history is committed to an append-only log with Falcon PQ anchoring. It still omits some operational details such as authentication, paid-route behavior, or side effects, but it discloses substantial non-obvious behavior.

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 reasonably short and not bloated, but it reads as value-proposition copy rather than structured operational guidance. It does not front-load the most decision-relevant fact for selecting the tool, such as 'given a need or URL, return a verified route.' It is acceptable, but not tight instruction.

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 22-parameter tool with no annotations and sibling tools to disambiguate against, the description is thin on operational context. It never explains how to choose route over preview/validate, how the need/url requirement works at a high level, or what makes a route 'strongest.' The output schema reduces some burden, but the missing usage context is still significant.

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?

The input schema already covers all 22 params with detailed descriptions, so the baseline is 3. The tool description adds no parameter-level guidance, but the schema itself is rich enough that no compensation is needed.

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 goes beyond the name by saying the tool 'finds the strongest x402 route' across Base, Solana, and Algorand, 'verifies it live,' and 'shows the evidence.' That is a clear verb+resource. It does not explicitly distinguish itself from sibling tools preview and validate, so it loses the fifth point.

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 explicit guidance about when to call route versus preview or validate. The 'right before spending' clue implies payment-time use, but it is not framed as a decision rule or contrasted with sibling tools. An agent is left to infer when this tool is the right choice.

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

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

With no annotations provided, the description carries the full burden and discharges it well: it discloses that the call is free, that SSRF protection fails closed (a meaningful safety posture an agent should know), and the return shape. It omits error/edge-case behavior, but for a low-stakes probe tool this is a reasonable level of disclosure.

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?

Four brief clauses with zero waste; the most decision-relevant traits (cost-free, fail-closed) are front-loaded and the return contents are conveyed in one sentence. Every element earns its place.

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 one-parameter probe with an output schema, the description is near-complete: purpose, safety posture, cost, and return contents are all present. No critical information an agent needs to invoke it correctly appears to be missing, aside from explicit sibling routing.

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% — the sole `url` parameter is already described as the https seller endpoint to probe. The description reinforces the seller-URL intent and implies https strictness via 'Fail-closed SSRF,' but adds little meaning beyond the schema, so the 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?

The description states a specific action — probing a seller URL to assess whether it is 'agent-ready' — and enumerates concrete outputs (readiness, claimed vs observed, flags). This clearly differentiates it from the siblings preview and route, which imply rendering and navigation rather than validation.

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 'Unpaid probe' qualifier and 'Does not charge' signal that this is a cheap pre-check to run before costlier operations, which implies a usage context but the description never explicitly names the alternative tools or states when not to use it. The 'check-first' role is implied, not declared.

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