Legacy

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered elsewhere. The description adds a little useful behavior (it returns "our name" per number for confirmation), but says nothing about invalid/unknown numbers, partial results, or batch limits.

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 short sentences, front-loaded with the action and ending with the motivating outcome. Mildly redundant in the second sentence, but 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?

With an output schema present, the description need not explain return values, and with a single well-constrained parameter it covers what the tool does and why. The main gap is error/edge-case behavior for unrecognized charity numbers.

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?

Reported schema coverage is 0%, but the schema itself supplies an example charity number and the pattern/format for both England & Wales and Scotland, so the description's "by charity number" adds no new format detail. It hints at batch behavior with "for each number" but never states the plural array or the 20-item cap.

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 verb and resource ("look up UK registered charities") and adds a distinguishing scope detail ("which can take a gift through Legacy"). It is clearly separable from the payment-oriented siblings create_checkout_link and quote, though it does not explicitly reference 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?

Usage is only implied: "so you can confirm it is the charity the donor meant" hints at a verification step before donation/checkout, but there is no explicit when-to-use, when-not-to-use, or named alternative. An agent can infer intent but is not told what to do with the result.

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/non-destructive, so the safety profile is partly covered, and the description usefully adds the donor-side flow (Gift Aid, optional tip, card payment) and that amounts remain the donor's to change. It says nothing about the link's lifecycle, persistence, or expiry, and notably never asserts the write implied by the tool name.

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?

A single efficient sentence with no filler, front-loading the artifact and then the donor experience. It is compact for the amount of behaviour it conveys.

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 return values need no explanation, but for a creation tool the description omits everything an agent would want: whether the link is persisted, shareable, single-use, expiring, or reusable given idempotentHint. Adequate but with clear 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?

The top-level `charities` parameter has 0% schema description coverage, and the description only partially compensates: 'with these charities' confirms the array's role and 'the amounts when given' signals that amount is optional. It adds no detail on the 1–6 item limit or the charity-number format, which the nested schema does 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 names the artifact ('a link to Legacy's checkout with these charities') and sketches the donor journey, so the resource is identifiable, but it never states the action of *creating* that link — only the title carries the verb. It also gives no signal distinguishing it from siblings check_charities or quote.

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 when-to-use guidance, no prerequisites, and no routing against the sibling tools. An agent must infer from the name alone when to call this versus quote or check_charities.

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 it is read-only, idempotent, non-destructive, and closed-world. The description adds valuable context about what it returns (donor cost, fees, charity shares, optional Gift Aid) and notes the assumptions around Gift Aid/tip. It does not discuss rate limits or authentication, but for a safe read operation that additional context is appropriate.

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 brief and front-loads what the calculation yields. It is slightly conversational but no sentence is wasteful; the assumptions note 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?

The tool has an output schema and rich annotations, so the description needn't explain return formats or safety. It does cover the main outputs and the Gift Aid/tip assumption, making it mostly complete for the tool, though sibling routing could be clearer.

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 67%, and the schema itself already documents Gift Aid, charityNumber, amount, and tipPercentage in detail with examples. The description mentions Gift Aid and tips only at a high level, adding little parameter meaning beyond what the schema provides. 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 this is a pricing/quote tool that breaks down donor cost, fees, charity shares, and Gift Aid. It does not explicitly contrast itself with siblings like check_charities or create_checkout_link, so it misses the top score for sibling differentiation.

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 (you invoke it to get price breakdowns), but the description offers no explicit when-to-use, when-not-to-use, or alternative-tool guidance. It does not tell the agent how this relates to check_charities or create_checkout_link.

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