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

Goes beyond the annotations by disclosing that nothing is persisted and that the caller owns the running totals — an important property that prevents an agent from assuming the check tracks spend itself. It also previews the is_allowed/remaining/violations outcome, though with an output schema present that detail is partly redundant. Idempotency and read-only safety are already covered 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?

Three tight sentences: purpose first, then the stateless calling contract, then the return shape. No filler; every clause carries information an agent needs.

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 annotations covering the safety profile and an output schema covering return values, the description supplies the remaining critical fact — statelessness and caller-owned totals. It leaves minor ambiguity about cap boundary behavior and default resolution, but nothing that would cause a miscall.

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 the schema already labels spent_today/spent_month as '(caller-supplied)' and defines each cap's meaning and defaults. The description reinforces the caller-supplied totals but adds no format, units, or boundary semantics (e.g., inclusive vs exclusive caps) beyond the schema, 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 ('guardrail ... proposed spend') and resource ('per-transaction, daily and monthly caps'), and the scope is unambiguous. No sibling in the list (token rates, mandates, x402, ISO 20022 conversions) overlaps, so an agent can select this tool without opening the schema.

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?

Gives clear operating context: it is stateless and the caller must supply spent_today/spent_month running totals rather than relying on stored state. It does not state when-not-to-use it or name alternatives, but no sibling competes for this job, so the omission is low-cost.

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?

Description details what is checked (fields, cap, expiry, proof) and that output includes 'ok plus violations and warnings.' Annotations already declare readOnly and idempotent, so description adds behavioral context without contradiction.

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: purpose, output, usage instruction. No wasted words, front-loaded with key 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?

Given parameter complexity (mandate object with many fields) and existence of output schema, description sufficiently covers when and how to use. Mentions return format and prerequisite step.

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%, baseline 3. Description adds meaning by explaining 'as_of' is for expiry check and 'mandate' is the canonical object from normalize tools, providing context beyond schema descriptions.

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?

Description clearly states the tool checks a mandate before payment conversion, listing specific checks (fields, cap, expiry, proof). It distinguishes from sibling normalize and convert tools by positioning as a guardrail step.

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?

Explicitly says 'Run this before converting,' indicating it should be used before to_pain001 or to_pacs008. Does not exclude other uses but provides clear context.

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 readOnly, openWorld, non-idempotent and non-destructive, so the safety profile is covered. The description adds genuinely new context: it reaches an external service, the rate is a live spot price rather than a guarantee, and an optional 'oracle' extra must be installed. The 'never moves money' clause largely restates destructiveHint=false, which keeps it out of 5 territory.

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?

One dense but well-ordered passage: purpose, use case, supported values, install prerequisite, then the risk caveat. Every sentence earns its place, though the install and caveat clauses could be trimmed slightly.

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?

Output schema exists, so return values need no explanation. The description covers prerequisites, external dependency, supported inputs, and the non-guarantee caveat — everything an agent needs to invoke it correctly.

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 both parameters (token_symbol, fiat_currency with default USD) are fully documented in the schema. The description's token list merely echoes the schema, adding no syntax or format detail beyond it, 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?

Specific verb (fetch) + resource (spot token->fiat exchange rate) + named provider (CoinGecko public API) + a concrete use case (pricing an x402 mandate in fiat). None of the sibling tools overlap, so the agent can route unambiguously.

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?

Gives a clear usage context ('to price a crypto-denominated (x402) mandate in fiat') and states the supported token set. It does not name an alternative or an explicit when-not-to-use, but no sibling tool competes for this job.

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 provide readOnlyHint, idempotentHint, and destructiveHint, which the description does not contradict. The description adds behavioral context by explaining the transformation to a canonical format and its consumption by other tools.

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 a single, concise sentence that efficiently conveys the tool's purpose without any extraneous 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 presence of an output schema and annotations covering safety, the description adequately completes the context for a transformation tool. It lacks some detail on the canonical mandate format but the output schema likely fills that 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 coverage is 100% with a clear description for the only parameter 'payload'. The description does not add significant additional meaning beyond what the schema already provides, so it meets the baseline.

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 clearly states the verb 'normalise', the specific resource 'Google AP2 mandate payload', and the outcome 'canonical mandate the other tools accept'. It effectively distinguishes from sibling tools like 'normalize_x402' by specifying the AP2 format.

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 clearly indicates the tool is for AP2 payloads, which helps differentiate it from sibling normalizer 'normalize_x402'. However, it does not explicitly state when not to use it or provide alternatives beyond the implied sibling context.

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, so the safety profile is covered. The description adds genuine behavioral context: it states it errors on unsupported tokens and that it returns amount plus decimals, which the annotations do not convey.

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 short sentences, front-loaded with the core conversion action and its basis, followed by return values and the error case. No filler and every clause carries 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?

An output schema exists, so the return shape need not be described, yet the description still summarizes it briefly. Combined with the annotation-covered safety profile and the documented error case, an agent has what it needs; only explicit when-to-use routing between siblings 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?

Schema description coverage is 100%, so the baseline is 3, and the description earns an extra point by specifying the supported token set with explicit decimal values (USDC/USDT/EURC=6, SOL=9, ETH=18), which meaningfully constrains valid token_symbol inputs beyond what the schema declares.

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 ('normalise') and a precise resource ('raw on-chain base units' to 'human token amount'), and even names the conversion basis. It is clearly distinguishable from siblings like normalize_x402 or normalize_ap2, which normalise entirely different payload types.

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 purpose implies when it applies (converting raw base units for display/human-readable output), and it notes it errors on unsupported tokens, which is a useful boundary. However, it never explicitly states when to reach for this versus another tool, nor does it name any alternative, so guidance is only implied.

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 idempotentHint=true, indicating no side effects. The description adds that the output is a canonical mandate, which is useful context but does not disclose error handling or validation 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?

Single, well-structured sentence with no redundancy. Front-loads the action and outcome.

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 open input schema (additionalProperties: true) and existence of an output schema, the description provides a high-level transformation purpose. However, it lacks details on what constitutes a valid x402 payload, which an agent might need to construct inputs.

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%, so the schema already documents the single parameter. The description adds only 'An x402 payment payload.', which is generic and adds minimal semantic value beyond the parameter name.

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 clearly states the action (normalize), the source format (Coinbase x402 payment requirement/receipt), and the output (canonical mandate). It distinguishes itself from sibling normalize_ap2 by naming the specific source protocol.

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 implies this tool is a prerequisite for other tools like check_mandate, to_pain001, etc., by mentioning 'the other tools accept'. However, it does not explicitly state when to use this over normalize_ap2 or provide any exclusions.

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, so the safety profile is clear. The description adds valuable context about the output format (using pacs.008 field names) and business purpose, which goes beyond 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 a single, well-structured sentence that front-loads the main action. Every word serves a purpose, 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 presence of a detailed input schema and output schema, the description is adequately complete. It explains the tool's purpose and output format. The only minor gap is a lack of explicit prerequisite reference (e.g., mandate must be canonical from normalize tools), but this is covered in 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?

The input schema provides 100% coverage for the mandate parameter, so baseline is 3. The tool description does not add new information about the parameter itself; it focuses on the output. No additional semantics provided beyond the 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 clearly states the verb 'convert' and the resource 'canonical mandate into a pacs.008 record', explaining its use for interbank settlement of an agent-authorised payment. This distinguishes it from siblings like to_pain001 (which produces pain.001) and normalize 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?

The description implies usage for converting a canonical mandate to a pacs.008 record for interbank settlement, providing clear context. However, it does not explicitly mention when not to use this tool or compare it to alternatives beyond the implicit purpose.

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?

The description discloses that the tool performs a conversion using 'exact field names pain001 expects', which adds behavioral context beyond the annotations. Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description's transformation nature aligns with these. No contradictions observed.

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 long, front-loaded with the action, and contains no extraneous words. Every part serves a purpose: defining the conversion, specifying the output format, and indicating the downstream use.

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 simple parameter set (1 required parameter with full schema coverage), the description adequately explains the tool's purpose and workflow integration. It mentions the output format and downstream tool, which is helpful. The existence of an output schema (not shown) further reduces the need to describe return values. Minor gap: no mention of error handling or validation.

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 the 'mandate' parameter is comprehensive, listing expected fields and referencing normalization tools. The description adds value by stating 'using the exact field names pain001 expects', which clarifies the mapping goal beyond the schema's listing of fields.

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 clearly specifies the verb 'Convert', the resource 'canonical mandate into a pain.001 record', and the intended use case 'for wire-valid XML'. It differentiates from siblings by mentioning the specific output format (pain.001) and the expected input (canonical mandate as from normalize_ap2/normalize_x402), making it distinct from to_pacs008 and others.

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 implies usage context by stating the output 'feeds straight into pain001 generate_message', indicating a downstream tool. Sibling tools like to_pacs008 and normalize_* steps suggest different stages in a workflow, but no explicit 'when to use' or 'when not to use' guidance is provided, though the context 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 cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description still adds real value by disclosing the exact validation semantics: field presence/well-formedness plus a deadline-vs-now_timestamp comparison, and that violations are returned rather than throwing. It never says whether the EIP-712 signature itself is recovered/verified, which is the one notable ambiguity for a tool named 'validate_eip712_permit'.

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, fully front-loaded: the validation contract first, the return value second. No filler and every clause carries 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?

With an output schema present, the description need not explain is_valid/violations in detail, and it covers both inputs and the validation rules. The only gap is the ambiguity over signature verification, which leaves a small hole for a tool whose name emphasizes EIP-712 signing.

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%, so the baseline is 3, but the description adds meaning beyond the schema by enumerating the required permit subfields and clarifying that now_timestamp is caller-supplied and used specifically as the deadline comparison point. That is a genuine increment over the schema text.

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 (validate) and a precise resource (EIP-2612 permit), then enumerates the concrete checks applied. The narrow domain immediately separates it from siblings like check_mandate, validate_mandate_expiry, and verify_x402_signature without needing to name them.

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 validation rules imply the intended use (pre-flight checking of a permit before submission), but there is no explicit statement of when to call this versus verify_x402_signature or check_mandate_expiry, nor any exclusions. Usage is inferable rather than stated.

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, idempotentHint and destructiveHint=false, so safety is covered. The description still adds genuinely useful behavioral context beyond that: the server never reads the clock, so results depend entirely on the caller-supplied now_timestamp, making it a pure deterministic function.

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 short sentences, front-loaded with the operation and its units, then the key semantic constraint, then the return value. 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?

For a pure two-parameter comparison tool with full schema coverage, annotations covering safety, and an output schema, the description supplies everything an agent needs: units, comparison direction, clock source, and return field.

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%, so the baseline is 3, but the description earns above baseline by clarifying that now_timestamp is caller-supplied (not server clock) and by defining the comparison direction (valid while now < expiration), which the schema alone does not convey.

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 and resource (check a mandate's expiry) and pins down the exact mechanism (unix-epoch seconds comparison). It is clearly narrower than the sibling check_mandate, but it never names that sibling to make the distinction explicit.

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 explains the comparison semantics ('valid while now is before expiration') which implies when the tool applies, but gives no explicit when-to-use or when-not-to-use guidance, and does not mention check_mandate as the alternative for a fuller mandate inspection.

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 establish readOnly, idempotent, non-destructive, closed-world behavior, but the description goes further by disclosing the verification algorithm (recover signer with eth_account), the case-insensitive address comparison, and the returned fields. No failure modes or malformed-signature handling are described, which keeps it short of a 5.

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 tight sentences, front-loaded with purpose and mechanism; the second sentence about return values is mildly redundant given the output schema but costs little.

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?

An output schema exists and annotations cover the safety profile, so the description only needs to convey mechanism and comparison semantics, which it does fully. Nothing essential for correct invocation 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?

Schema description coverage is 100%, so all three parameters are documented in the schema; the description only reinforces mandate_json as the signed payload and adds the case-insensitive comparison detail. With the schema doing the heavy lifting, 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?

States a specific verb (verify) and resource (x402 EIP-191 personal_sign over the mandate JSON), and names the recovery mechanism (eth_account) so an agent can distinguish it from the EIP-712 sibling validate_eip712_permit without opening either schema.

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?

Usage is implied by the signature scheme named in the description (EIP-191 personal_sign over mandate JSON), which implicitly routes the agent away from validate_eip712_permit. However, no explicit when-to-use/when-not statement or named alternative is given, so the agent must infer the boundary itself.

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