US Nonprofit & Charity Check MCP

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

No annotations exist, so the description carries the full burden; it partially discharges that by enumerating the specific fields returned and flagging the PRO tier. It does not state that the operation is read-only, whether multiple years come back as a list, how many years of history are covered, or what the behavior is for non-990 filers or invalid tokens.

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 front-loaded sentence that leads with tier and scope, then enumerates the returned data – zero padding. The leading "PRO." is terse and slightly cryptic without context, but it is placed first where it matters most.

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 no annotations and no output schema, the field enumeration does real work to describe the return payload. Still missing for a 2-param tool is the response shape (single object vs. multi-year series) and access-failure behavior, leaving gaps an agent would want closed before calling.

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%: access_token is documented in-schema, while ein has no schema description. The description compensates for ein by saying the data is "for an EIN," clarifying it is the organization identifier, though it adds no format/lookup details (e.g., whether dashes are accepted).

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+resource: Form 990 financial history for an EIN, and enumerates the exact data domains returned (revenue, expenses, assets, liabilities, officer comp, program/overhead ratio). It is clearly a financial-detail tool rather than a status check or prospect list, so an agent can route it away from nonprofit_check/prospect_list, but the description never names those siblings to make the contrast 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?

"PRO." signals that a paid/subscriber credential is required, and the access_token param reinforces this, giving an implied precondition. However, there is no explicit guidance on when to choose this over nonprofit_check or prospect_list, and no statement about what happens for organizations that don't file a 990.

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 full behavioral burden. It usefully discloses that the lookup is FREE, returns only the top 3 matches, and includes city, state, and 501(c) type, but it omits read-only confirmation, matching behavior, auth needs, and error/empty-result 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?

The description is a single front-loaded sentence fragment with no wasted words. The key action, scope, search keys, result limit, and returned fields are all packed efficiently.

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 is simple and has no output schema, so describing the top-3 return fields is helpful. Still, with no annotations and 0% schema description coverage, the description is not fully complete: it leaves the state parameter unexplained and creates ambiguity by mentioning EIN when no EIN parameter exists.

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 0%, so the description should compensate for both parameters. It mentions lookup by name or EIN but the schema has only name and state, and the state parameter is never explained; the EIN mention is not reconciled with 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 uses a specific verb ("Find") and resource ("US nonprofit/charity"), and states the search keys and returned fields. It is clear enough to distinguish this as a lookup tool, though it does not explicitly differentiate itself from siblings like financials or prospect_list.

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 "Find a US nonprofit/charity by name or EIN," so an agent can infer this is for nonprofit lookups. However, it gives no explicit when-to-use guidance, exclusions, or comparison to the sibling tools financials and prospect_list.

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 carries the full burden of behavioral disclosure. It only says 'PRO' and describes the matching criteria; it does not state whether the operation is read-only, what access_token requirements exist, whether results are paginated or rate-limited, or what the response contains.

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 compact and front-loaded, with no redundant sentences. The unexplained 'PRO.' tag is slightly distracting and the core purpose is expressed as a noun phrase rather than an explicit action, but overall it is efficiently 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?

For a four-parameter search tool with no annotations and no output schema, the description omits important context: authentication/token behavior, pagination, return fields, result limits, and how this tool relates to nonprofit_check or financials. It gives enough to infer the basic search but not enough for an agent to invoke it with full confidence.

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 only 25%, so the description should compensate for undocumented parameters. It adds useful meaning for keyword and state filtering with concrete keyword examples, but it does not explain the page parameter, and access_token is described only in 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 identifies a specific resource (nonprofits) and filters (keyword, state) with examples such as 'food bank', 'hospital', and 'school'. It is clear enough to understand the core search purpose, but it phrases the action as a noun phrase rather than an explicit list/search verb and does not differentiate itself from sibling tools like nonprofit_check or financials.

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 names target users (fundraising consultants, SaaS, and grant writers), which implies a prospecting use case for this tool. However, it gives no explicit when-to-use vs. when-not guidance, no prerequisites, and no comparison to the sibling tools nonprofit_check or financials.

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