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

Annotations already declare this as a safe read (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description nonetheless adds meaningful behavior by stating the 50-key ceiling and describing what comes back (source/schema/traffic excerpts per finding), which matters because there is no output schema. It stops short of saying how missing or invalid keys are handled.

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 sentences with zero filler: the operation and its keying come first, the return payload second. Nothing is duplicated or padded.

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 two-parameter read tool with no output schema, the description supplies the essential return-content picture and the batch limit. Remaining gaps are partial-result and error behavior, which are minor but non-trivial for a batch-key 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 coverage is 100%, so both parameters and the 1–50 item bounds are already documented. The description's key example (EV-000123) and 50-key limit largely restate schema content rather than adding new semantics, so 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?

States a specific verb+resource: fetch citation evidence snippets by key for a named legacy system, and clarifies it is the excerpt backing a cited finding. That is clearly distinct from siblings like get_legacy_system or get_legacy_parity, though the description never names an alternative explicitly.

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 'backing each cited finding' and the key format, but the description itself gives no when-to-use/when-not guidance and does not name get_legacy_system as the place to obtain keys — that pointer exists only in the schema. An agent must infer the call sequence.

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