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

Discloses API source (ProPublica with IRS e-File fallback), refresh semantics, rate limit, no-auth requirement, and return fields, all beyond the read-only and idempotent annotations. It also provides a report_feedback fallback instruction if the response is insufficient. 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 front-loaded with purpose and key outputs, then adds API source, rate limit, auth, and feedback routing—each sentence adds operational value. It remains focused despite providing rich context.

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 one simple parameter, annotations, and an output schema, the description covers invocation context, expected return fields, source behavior, and failure fallback. An agent has enough to select and call the tool correctly without needing additional inference.

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% and the only parameter, ein, is already fully explained with format and required status in the schema. The description adds no additional parameter-level meaning, so the baseline 3 applies.

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 states it performs complete nonprofit due diligence in one call, listing revenue trends, executive pay, risk flags, and a health score from IRS 990 data. This clearly distinguishes it from sibling tools like nonprofit_fetch_nonprofit_by_ein or nonprofit_fetch_nonprofit_financial_trends.

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 identifies target users (grant-makers, investors, compliance teams) and frames the tool as a one-call comprehensive due diligence option, giving clear context for when it fits. It does not explicitly name alternative sibling tools 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.