charity-registry

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the description doesn't need to restate safety. It adds useful return behavior by listing the specific computed metrics and noting the verdict is deterministic, which is especially valuable given there is no output schema.

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 concise sentences with no filler. The core comparison behavior and constraint are front-loaded, followed by the returned fields and the use case, making it easy to parse quickly.

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 simple one-parameter, read-only tool, the description covers the key returned fields and the intended use case. It does not define 'strongest transparency signal' or describe error behavior, but the schema constrains input bounds and annotations cover safety, so the description is reasonably 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 input schema has 100% coverage with a clear description for the single 'slugs' parameter, including min/max items. The description repeats '2-5' and 'by slug' without adding extra semantic detail such as slug format, source, or examples, so it stays at the baseline for full 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 a specific verb and resource: side-by-side comparison of charities by slug. It enumerates the exact returned data and includes a deterministic verdict, and the use case 'choose between named charities' distinguishes it from sibling tools like search or verify.

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 explicitly says 'Use this when the user wants to choose between named charities,' giving a clear when-to-use trigger. It does not explicitly name alternatives or when-not-to-use conditions, but the stated use case is sufficient to route an agent correctly.

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 read-only, idempotent, and non-destructive behavior. The description adds meaningful behavioral details beyond annotations: it returns up to `limit` results, restricts to the same country and category, and excludes the input charity. This gives an agent a clear model of the tool's 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?

Three short sentences, each earning its place: the core behavior, the use case, and an important exclusion detail. The most critical information is front-loaded, with 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 simple lookup tool with rich annotations, the description is largely complete. It covers inputs, selection criteria, limit behavior, and exclusion. Since there is no output schema, the return format could be specified a bit more, but 'other charities' is a reasonable description.

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 50%, so the description partially compensates by explaining that `limit` controls the maximum number of returned charities. The slug parameter is described in the schema, and the description reinforces its role as the source charity. This adds value beyond the structured 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 a specific verb ('return'), a resource ('other charities'), and precise selection criteria ('same country + category' and 'same country + category'). It also clarifies that the input charity is excluded from results, clearly distinguishing this from search_charities.

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 gives clear usage context: 'Useful for find more like this recommendations.' This implies the intended scenario well. It does not explicitly name alternatives or state when not to use it, so it stops 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?

Annotations already cover safety profile (readOnlyHint, idempotentHint, destructiveHint). The description adds valuable behavioral details: case-insensitive substring matching, limit semantics, and the specific response fields. This goes beyond what annotations 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?

The description is three sentences with no wasted words. The core action is front-loaded, followed by usage context and matching behavior. Every 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?

The description covers the essential trigger scenario, parameter behavior, and return fields, which is complete for a simple read-only search tool despite lacking an output schema. The only gap is not addressing how this tool relates to sibling tools that might also perform searches, like find_similar.

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 67%, meaning the limit parameter lacks schema-level description. The description compensates by explaining that 'Returns up to limit matches' and by defining query as a case-insensitive free-text name search. Country is already described in the schema, but the added clarity for query and limit is meaningful.

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: 'Search the charity registry by free-text name' and lists the return fields. This is a specific verb and resource. However, it does not explicitly distinguish itself from sibling tools like find_similar, so it falls short of a 5.

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?

Provides an explicit usage scenario: 'Use this BEFORE resources/read when the user names a charity but you don't know its slug.' This is clear context for when to use it. It lacks explicit guidance on when not to use it relative to the listed siblings (compare_charities, find_similar, verify_charity).

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, idempotenteHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: it accepts country-specific identifier formats and explicitly states 'Returns the matched charity or null,' which is important for agents deciding how to handle a not-found result.

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 with no filler: the first sentence front-loads the action and accepted identifier types, and the second provides usage guidance. Every clause contributes essential 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?

For a simple read-only tool with two clearly described parameters and no output schema, the description covers the important operational details: what identifier to pass per country, what the result will be (charity or null), and when to use the tool. Nothing critical 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 baseline is 3. The description adds meaningful context by enumerating concrete identifiers per country (EIN, Charity Commission number, RSIN, AHU/Kemenkumham) and clarifying that id_value can be a generic registration_number, which helps agents correctly map user input to the expected parameter.

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 ('Look up'), a clear resource ('a charity'), and the precise scope (by official registry identifier, with country-specific examples). It distinguishes itself from siblings like search_charities and compare_charities by emphasizing exact registry verification and returning null when no match exists.

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 explicitly states when to use the tool: 'Use this when the user provides a registry number and wants to confirm what's registered under it.' It does not explicitly name alternatives or exclusion conditions, but the context makes it clear this is for exact registry lookups, not fuzzy search or comparison.

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