merona — x402 settlement index

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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses the calculation logic (wash-adjusted, removing funded loops and self-dealing cycles), the potential orders-of-magnitude difference from raw totals, and the return contents (clean settlement count, volume in USD, as-of date). It also emphasizes no cost and no API key, which are behavioral facts not captured by 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 three sentences long: first sentence states the purpose and key caveat, second sentence enumerates the return fields, and third sentence covers access requirements. Every sentence adds value; no filler words.

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?

Given the tool has no parameters and an output schema exists, the description is comprehensive. It explains what is returned, the statistical significance of the numbers, and the access requirements. It also addresses potential confusion about why these figures differ from raw transfer totals.

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 tool has zero parameters, so the schema is fully covered. The description explicitly states 'Takes no arguments', reinforcing the schema. Since there are no parameters to explain, this is a solid baseline for parameter semantics.

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 uses a specific verb phrase 'Get wash-adjusted x402 settlement volume per chain' and clarifies the core value proposition (spend that survives removal of funded loops and self-dealing cycles). This clearly states what the tool does and differentiates it from siblings, which are unrelated tools.

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 provides implicit usage guidance by explaining the difference from raw transfer totals and indicating that these are the figures published on merona.io. It also states 'Takes no arguments. Free, no key' which sets expectations for usage. There is no explicit alternative exclusion, but the unique purpose is clear.

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?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context: data source ('merona's nightly probe'), scope ('public catalog'), output contents ('advertised vs live addresses, full counts and as-of dates'), and the complete feed URL. 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 front-loaded with the core action and subject, then adds necessary context in short, clear sentences. Every clause earns its place: source, output details, complete feed link, no-args, no-key, and alternative tool.

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 zero-argument, read-only feed with an output schema and annotations, the description fully covers purpose, source, limitations (top 10 vs. complete feed), the alternative tool, and access requirements. Nothing critical is missing.

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 tool has zero parameters, and the input schema is empty. The description explicitly confirms 'Takes no arguments,' which is consistent with the schema. With no parameters to elaborate on, baseline 4 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 a specific verb ('List') and a precise resource ('x402 endpoints currently advertising one payout address while asking payers for another'), making the tool's purpose unmistakable. It also distinguishes itself from the sibling tool payto_check by explicitly directing targeted lookups there.

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 provides explicit usage guidance: 'Use payto_check instead when you already have a specific address or endpoint to check.' It also clarifies that the tool takes no arguments, is free, and requires no key, giving clear conditions for use.

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?

Annotations already declare readOnlyHint and idempotentHint, but the description adds valuable context about how to interpret results: 'Records are dated facts, not accusations' and 'no record found is not a clearance'. It also discloses access requirements ('Free, no key') and clarifies the tool's scope by distinguishing it from the broader mismatch_feed.

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?

Three sentences deliver purpose, usage timing, return values, alternative tool, and interpretation caveats without redundancy. The first sentence immediately states the core function, and every subsequent sentence 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?

Despite having only one parameter, the description covers when to use, what it returns (mismatch, rotation history, on-chain settlement), how to interpret results, and points to the alternative tool. With a robust output schema and annotations, this is fully complete for a read-only lookup tool.

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 schema description for query already covers the full input semantics ('Wallet address (0x… or base58) or endpoint URL/hostname'), so the description's mention of 'wallet address or endpoint URL' adds no new meaning. With 100% schema coverage, a 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 a specific verb and resource: 'Check whether an x402 endpoint or wallet pays out where it claims to', making the tool's function unmistakable. It further differentiates from siblings by explicitly directing users to mismatch_feed for listing every known mismatch.

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 explicitly states when to use the tool ('before your agent sends funds') and identifies the alternative for a different need (mismatch_feed). The warning 'no record found is not a clearance' provides critical usage guidance and prevents misinterpretation.

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?

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds meaningful behavioral details: the score is wash-aware, includes multi-hop cycle detection, provides a snapshot SHA for independent re-derivation, and explains the free vs. paid settlement-receipted response path. 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 two sentences, front-loaded with the primary purpose. Every clause adds useful information—the output features, the free nature, and the optional payment—with no redundancy or 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?

Given the tool's moderate complexity, the description covers the core use case, free vs. optional payment behavior, and key output characteristics. An explicit alternative to sibling tools and potential edge cases would improve completeness, but the presence of rich annotations and an output schema means the description doesn't need to over-explain.

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 baseline is 3. The description goes beyond the schema by explicitly stating that chain and address are required, and by giving a concrete usage example for the optional payment parameter ('pass payment=<base64 X-PAYMENT payload>'). This adds value over the raw schema.

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 a specific verb+resource: 'Score a specific seller wallet before paying it'. It details the output (wash-aware m.Score, A–F grade, component breakdown, wash flags, snapshot SHA), distinguishing it from sibling tools that handle stats, mismatch feeds, or payment checks.

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 provides clear usage context: score before paying a seller, and it's free with no key or payment needed. It also explains the optional x402 payment path. However, it does not explicitly contrast with sibling tools or give when-not-to-use scenarios, so it falls short of a 5.

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