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

Annotations provide readOnlyHint=true and openWorldHint=true, indicating this is a safe read operation with potentially dynamic data. The description adds that it uses 'latest exchange rates', which implies real-time or recent data, but doesn't specify source, update frequency, or accuracy limitations. No contradiction with annotations exists.

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, efficient sentence that directly states the tool's function without unnecessary words. It's front-loaded with the core action and includes the key constraint ('latest exchange rates').

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 read-only tool with no output schema and rich schema coverage, the description is minimally adequate. It covers the basic operation but lacks details on output format (e.g., numeric result with currency), error handling, or sibling tool differentiation, which could aid the agent in proper 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 description coverage is 100%, with clear parameter descriptions and enums for currencies. The description adds no additional parameter semantics beyond what's in the schema, such as format examples or constraints. With high schema coverage, the baseline score 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 clearly states the tool's purpose with a specific verb ('converts') and resources ('amount from one currency to another'), and specifies it uses 'latest exchange rates'. However, it doesn't explicitly differentiate from its sibling 'convert_currency_specific_date', which is a similar conversion tool but for historical dates.

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 no guidance on when to use this tool versus its siblings. It mentions 'latest exchange rates' but doesn't explicitly state that this is for current conversions only, nor does it reference the historical alternative 'convert_currency_specific_date' or other related tools like 'get_latest_exchange_rates'.

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 adds valuable behavioral context beyond annotations: it explains the fallback mechanism ('If there is no exchange rate available for the specific date, the rate for the closest available date before the specified date will be used'). Annotations provide readOnlyHint=true and openWorldHint=true, which the description doesn't contradict. The description enhances understanding of the tool's behavior with historical data.

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 extremely concise and front-loaded: the first sentence states the core purpose, and the second sentence adds crucial behavioral detail about fallback logic. Every sentence earns its place with no wasted words. The structure is clear and efficient for an AI agent to parse.

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 (currency conversion with date specificity), the description is reasonably complete. It covers the core purpose and important behavioral nuance (fallback logic). With annotations covering safety (readOnly) and data scope (openWorld), and no output schema, the description provides adequate context for an agent to understand when and how to use this tool, though it could benefit from more explicit sibling differentiation.

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%, with all parameters well-documented in the schema (amount, from_currency, to_currency, specific_date). The description doesn't add significant parameter semantics beyond what the schema already provides. It mentions 'specific date' but doesn't elaborate on format or constraints beyond the schema's YYYY-MM-DD format. Baseline 3 is appropriate given high schema coverage.

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's purpose: 'Convert an amount from one currency to another using the exchange rates for a specific date.' It specifies the verb (convert), resource (currency amount), and key constraint (specific date). However, it doesn't explicitly distinguish this from sibling tools like 'convert_currency_latest' beyond the date specificity implied in the name.

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 when to use this tool (when you need conversion for a specific historical date) through its focus on date-specific rates. However, it doesn't explicitly state when to choose this over alternatives like 'convert_currency_latest' or when not to use it (e.g., for real-time conversions). The fallback behavior for missing dates provides some context but not explicit comparative 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?

Annotations indicate readOnlyHint=true and openWorldHint=true, covering safety and data scope. The description adds valuable behavioral context: it explains fallback behavior ('closest date before' if unavailable), clarifies parameter requirements ('Either a specific date, a start date, or a date range must be provided'), and notes default behavior for symbols. 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 well-structured and front-loaded with the core purpose. Each of the four sentences adds distinct value: purpose, fallback behavior, parameter requirements, and symbols filtering. There is no wasted text, and it efficiently covers key aspects 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 (historical data with fallback logic) and rich schema/annotations, the description is mostly complete. It lacks details on output format (no output schema provided) and does not mention rate limits or authentication needs, but covers core usage, parameters, and behavior adequately for a read-only 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 baseline is 3. The description adds meaningful semantics: it explains the relationship between date parameters (specific_date vs. start/end date range), clarifies that symbols filter results (with default to all currencies), and mentions the fallback logic for unavailable dates, which the schema does not cover.

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's purpose: 'Returns historical exchange rates for a specific date or date range.' It specifies the resource (historical exchange rates) and distinguishes from siblings like 'get_latest_exchange_rates' (historical vs. latest) and 'convert_currency_specific_date' (retrieval vs. conversion).

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 historical rates, with date or date range input. It implicitly distinguishes from siblings by focusing on historical data, but does not explicitly name alternatives or state when not to use it (e.g., vs. 'get_latest_exchange_rates' for current rates).

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 openWorldHint=true, indicating safe read operations and open-world data. The description adds context about filtering with symbols and default behavior, but does not disclose additional behavioral traits such as rate limits, data freshness, or error handling. No contradiction with annotations exists.

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 appropriately sized with two sentences that are front-loaded and efficient. It avoids redundancy and wastes no words, though it could be slightly more structured by explicitly separating purpose from usage notes.

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 (simple read operation), rich annotations (readOnlyHint, openWorldHint), and high schema coverage, the description is adequate but lacks details on output format, data sources, or limitations. Without an output schema, it should ideally hint at the return structure, but annotations provide some safety context.

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%, with detailed descriptions and enums for both parameters. The description adds minimal value by mentioning that symbols filter results and default to all currencies if not provided, which is already implied in the schema. Baseline 3 is appropriate as the schema does the heavy lifting.

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's purpose with a specific verb ('Returns') and resource ('latest exchange rates for specific currencies'). It distinguishes itself from historical tools but doesn't explicitly differentiate from sibling tools like 'get_supported_currencies' or 'convert_currency_latest' in terms of what makes this tool unique for retrieving rates versus conversion.

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 implied usage by explaining that symbols filter results and default behavior when symbols are not provided. However, it lacks explicit guidance on when to use this tool versus alternatives like 'get_historical_exchange_rates' or 'convert_currency_latest', and does not mention any prerequisites or 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 and openWorldHint=true, indicating a safe, non-destructive operation with stable data. The description adds minimal behavioral context by specifying the return format ('list of three-letter currency codes'), but doesn't cover aspects like response structure or potential limitations. No contradiction with annotations exists.

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, efficient sentence that directly states the tool's function without any wasted words. It's front-loaded with the core action and resource, making it highly concise and well-structured.

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 low complexity (0 parameters, no output schema) and rich annotations (readOnlyHint, openWorldHint), the description is minimally adequate. It specifies the return content but lacks details on format (e.g., array structure) or usage context, which could be helpful despite the annotations.

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?

With 0 parameters and 100% schema description coverage, the input schema fully documents the lack of parameters. The description appropriately doesn't add parameter details, as none are needed, aligning with the baseline for zero parameters.

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 ('Returns') and resource ('list of three-letter currency codes for the supported currencies'), making the purpose specific and understandable. It doesn't explicitly differentiate from siblings like 'get_historical_exchange_rates' or 'get_latest_exchange_rates', which focus on exchange rates rather than currency codes, so it misses full sibling distinction.

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 no guidance on when to use this tool versus alternatives. It doesn't mention use cases like needing currency codes for conversion tools or how it differs from siblings that handle exchange rates, leaving the agent without explicit context for selection.

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