Currency & Exchange Rate MCP

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

No annotations are provided, so the description carries the full burden. It discloses payment requirements, default date, and error handling (402). It does not mention if the tool is read-only or destructive, but the nature (sampling signals) implies read-only. The payment flow is well-explained.

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 paragraphs with clear topic separation: purpose and payment flow. It is front-loaded with the core action. However, it is slightly verbose with the payment details, but justified by complexity.

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 (mentioned in context signals), the description need not detail return values. It covers payment, defaults, and error handling. It could mention the free-tier counter more explicitly, but the agent_id parameter description covers it.

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%, but the description adds value by explaining the date default, agent_id scoping, and the payment_tx usage in re-call after a 402. This goes beyond the schema's 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?

The description clearly states the tool returns 'the top 5 signals from today's brief as structured JSON' and positions it as a 'cheap sample of the full daily_brief'. The verb 'Get' and resource 'signals' are specific, and it distinguishes itself from the sibling tool 'daily_brief'.

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 use when deciding whether to buy the full brief, and explicitly compares costs ('$0.50 USDC vs the full daily_brief price'). It also explains the 402 payment flow. It does not explicitly state when not to use, but 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?

With no annotations, the description carries the burden. It discloses that the conversion uses the latest ECB rate and returns the converted amount, rate, and as-of date. It does not cover rate limits, caching, or error scenarios, but the core behavior is adequately described.

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 main action. It is free of redundancy and gets straight to the point, even if the promotional 'FREE' could be considered fluff.

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 simplicity and the presence of an output schema (not shown but indicated), the description covers the essential inputs, outputs, and rate source. It could mention error handling or currency support limits, but overall it is sufficient for an agent to use the tool 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 coverage is 100%, so baseline is 3. The description adds context about ECB rates but does not provide additional constraints or clarifications beyond what the schema already gives (e.g., currency code format). The value added is marginal.

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 converts currency amounts using the latest ECB reference rate. The verb 'convert' and specific resource 'currency' are precise, and the tool is distinguished from sibling tools like 'rates' and 'historical_rate' by its action.

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 is the primary conversion tool by calling it 'the gateway tool every agent handling international transactions needs.' It does not explicitly state when not to use it or mention alternatives, but the sibling list provides context for differentiation.

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?

Despite no annotations, the description thoroughly discloses key behaviors: payment requirement, expiration, provenance attestation, and the mechanism for retrying after a 402 (via payment_tx or stripe_token). This exceeds typical transparency.

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 very concise yet comprehensive, with every sentence providing essential information. The first sentence states purpose, the second adds attestation detail, and the third covers payment and expiration. No redundant or vague phrasing.

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 full parameter schema coverage, the description covers all necessary aspects: purpose, payment flow, expiration, and authentication bypass. It is complete for effective tool usage.

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% and the description adds context beyond schema: explains that date defaults to today UTC, and clarifies that payment_tx and stripe_token are for re-calling after a payment demand. This adds meaningful usage guidance.

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 retrieves a curated daily FX brief with specific contents (largest 7-day movers, key cross-rates, snapshot date) and mentions provenance attestation. This distinguishes it from sibling tools like historical_rate or rates.

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 outlines payment requirement ($5 USDC), expiration at midnight UTC, and the flow for handling 402 responses. However, it does not explicitly guide when to use this tool over alternatives like brief_summary or rates, leaving some ambiguity.

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, the description carries full burden. It discloses the data source (ECB reference), fallback to nearest business day, payment mechanism ($0.005 after free allowance, 402 handling with payment_tx), and authorization bypass. It does not explicitly state that the tool is read-only or safe, but the nature of the operation (querying a rate) implies it. The payment details are well covered, earning a 4.

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 highly concise with two sentences in the first paragraph stating purpose and use cases, and a second paragraph detailing payment. It is front-loaded with the main action, and every sentence contributes meaning without redundancy.

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 complexity (5 parameters, output schema present, 100% schema coverage), the description covers the core functionality, data source, payment model, and re-call procedure. The output schema is not described but that's acceptable as it exists separately. Overall, it provides sufficient context for an agent to invoke the tool 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 coverage is 100%, so baseline is 3. The description adds value by explaining that the 'date' parameter uses the nearest prior business day and that 'payment_tx' is used in re-call after a 402. This enriches the semantic understanding beyond the 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?

The description explicitly states the tool retrieves the exchange rate for a currency pair on a specific past date using ECB reference and the nearest prior business day. It also lists use cases (back-dating invoices, settlements, historical accounting), clearly distinguishing it from siblings like 'convert' or 'rates' which likely handle current or real-time data.

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 context for when to use this tool ('For back-dating invoices, settlements, and historical accounting'), implying it is for historical data. However, it does not explicitly exclude other uses or compare with alternatives, 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.

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It states the tool provides 'details' and is free, but does not indicate whether it is read-only, requires authentication, or has any side effects. Even basic context like 'Returns data without modifying any state' is missing. The description minimally conveys the nature of the tool.

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 run-on sentence that mixes two ideas: protocol details and how to attest. It is relatively short but suffers from poor structure, combining a statement of fact with instructional content. The sentence could be split into two clear sentences for improved 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?

Given the tool has no parameters and includes an output schema, the description only needs to convey what information is returned. It mentions 'details' but does not specify the exact content (e.g., server list, documentation links). Sibling tools like 'rates' and 'daily_brief' are rate-focused, so mint_info likely fills a different niche, but more explicit description of the output would make it complete.

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 with 100% coverage trivially. The description does not need to add parameter semantics because none exist. Per the rubric, a baseline of 4 is appropriate when there are no parameters, as the description cannot add value 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 states that the tool provides 'FoundryNet Data Network + MINT Protocol details' and mentions its use for attesting FX conversions on-chain. The verb 'mint_info' implies informational retrieval, and the resource is the MINT protocol/network. While clear, it does not distinguish itself from sibling tools such as 'historical_rate' or 'rates', which serve distinct purposes. The purpose is specific but lacks a concise verb-resource pairing.

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 explicit guidance is provided on when to use this tool versus siblings. The description mentions it is 'FREE' but does not suggest scenarios (e.g., 'Use this to get an overview of the network before making conversions'). Sibling tools like 'convert' or 'rates' are not contrasted, leaving the agent with no clear selection criteria.

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?

Discloses source (ECB fix), output format (map plus date), and that it's free. With no annotations, this provides adequate behavioral context beyond basic functionality.

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, no filler. Front-loaded with the core action and source. Every phrase adds value.

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 single-parameter tool and existence of output schema, the description fully covers purpose, input, output, and source. No obvious gaps.

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 covers 100% of parameters, and description adds minimal extra meaning beyond stating 'base currency'. The default and ISO 4217 spec are already in 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?

Clearly states the tool gets current exchange rates for a base currency from the ECB reference fix, returning a map and date. Distinguishes from siblings like historical_rate by emphasizing 'current' rates.

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?

Implicitly suggests use for latest rates but does not explicitly contrast with siblings such as historical_rate or convert. No when-not-to-use guidance.

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, the description fully discloses behavioral traits: daily free allowance, $0.01 USDC cost after that, 402 error handling with Solana payment, and optional auth key bypass. This level of detail gives the agent complete expectations.

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 efficient with two paragraphs: first for purpose, second for payment/auth. It is front-loaded with key information and avoids extraneous text, though slightly longer than the shortest possible version.

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 high schema coverage, the description covers purpose, payment, and free tier well. It does not explain day bounds (already in schema) or other errors beyond 402, but is complete enough for a paid 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?

Schema description coverage is 100%, so the schema already documents all parameters. The description adds no additional semantics beyond the schema (e.g., does not elaborate on format or constraints), so baseline 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 clearly states the tool retrieves rate history, trend direction, percentage change, and volatility for a currency pair over N days. It uses specific verbs and resources ('get the rate history') and mentions use cases (FX risk, hedging, timing decisions), distinguishing it from generic rate 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 provides context for when to use the tool ('for FX risk, hedging, and timing decisions') and includes payment instructions that guide usage, but does not explicitly exclude alternatives among sibling tools.

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 provided, so description fully discloses paid calculation with daily free allowance and 402 handling. However, it could explicitly state that it is read-only (no state modification) and idempotent, but the payment logic implies a side effect of consuming credits. Still very transparent.

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 dense with important information but slightly verbose. Could be more structured with bullet points for methods and payment instructions, but still efficient and front-loaded with core purpose.

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 output schema exists, description covers all necessary context: purpose, usage, payment model, method options, and how to handle payment. No gaps for an agent to misuse the 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?

Schema description coverage is 100%, but description adds significant context: enumerates method options, explains payment_tx usage for re-call after 402, and notes agent_id for scoping free counter, enhancing semantics 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 tool calculates TOTAL landed cost of cross-border payment including FX spread, transfer fee, and settlement time, distinguishing it from siblings like convert or rates that likely only provide mid-market rates.

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 tells when to use (for total cost, recipient amount, cheapest rail) and implies not for simple mid-market rate. Also provides clear instructions for handling 402 payment and mention of free daily allowance with payment method options.

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