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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows this is a safe read operation. The description adds valuable context about the data's regulatory origin, the 7% net worth threshold, and an example output pattern. This goes beyond the annotations, though it doesn't discuss edge cases like name matching or state filtering.

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, starting with usage, then returns, followed by context, threshold, example, and source. The example is slightly long but illustrative and earns its place. Every sentence adds value, though it could be tightened.

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 lack of an output schema, the description lists the returned fields and provides a concrete example with realistic numbers. It also explains the well-capitalized threshold for interpreting net worth ratio. Missing explicit parameter semantics (state) and return format details, but overall it is fairly complete for a financial data lookup.

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 must compensate. It implies the credit union name is needed via the example but doesn't explicitly state that credit_union_name is required. The optional state parameter is entirely omitted, leaving agents without guidance on how state filtering works.

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 returns NCUA call report financials with specific fields (assets, deposits, loans, net worth ratio, delinquency rate, ROA) and peer comparison signals. The verb 'Returns' is specific, and the resource is unambiguous. It distinguishes itself from sibling benchmark tools by focusing on individual credit union financials rather than broad benchmarks.

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 provides usage contexts: 'Use when evaluating a credit union for partnership, acquisition, membership, or competitive benchmarking in a local market.' However, it doesn't name alternative tools or when-not conditions, which prevents a 5.

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