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

With no annotations provided, the description carries the full burden, and it does contribute real value by disclosing the auth mechanism and the header-less fallback. It says nothing about failure modes (invalid id, missing key), permissions, or what the returned vault contains, so the behavioral picture is only half-drawn.

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, the primary purpose front-loaded, and the auth caveat placed last where it belongs. No filler, though the parenthetical about generating keys in the web app is slightly tangential to invocation.

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 two-parameter read with 100% schema coverage, the description covers purpose and auth adequately. With no output schema, it could have sketched what a vault record contains, but nothing critical to making the call 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 coverage is 100%, so both parameters are already documented in the schema, and the description's note about api_key for header-less clients merely echoes the schema's own wording. Baseline 3 is appropriate when the schema does the heavy lifting.

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 and resource ('Returns a specific vault by id'), which cleanly separates it from the plural list_vaults and the more specialized get-code-vault-* siblings. It stops short of explicitly naming those alternatives, but the singular-scoped retrieval is unambiguous.

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?

There is no statement of when to use this tool versus list_vaults or the code-vault retrieval siblings; the agent must infer selection from the name alone. The sentences present are about authentication, not usage context.

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