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

With no annotations supplied, the description carries the full burden and does so: encryption at rest, injection only at send time, host-allowlist enforcement that refuses non-allowed hosts, the value never being returned, best-effort redaction of echoed values (with an explicit caveat that other encodings are not caught), overwrite semantics including hosts, and a 50-secret quota. These are exactly the non-obvious behaviors an agent cannot infer from the schema.

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?

Front-loaded with the purpose, then usage, then guarantees, then caveats — a sensible ordering with no filler sentences. It is dense and somewhat long, but nearly every clause conveys a distinct safety or lifecycle fact rather than restating the name.

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 three-parameter mutation tool with no annotations and no output schema, this covers everything an agent needs: how the secret is referenced later, where it may be sent, what happens on overwrite, what is visible in responses, and the quota. Nothing material is left for the caller to guess.

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 constraints like the name pattern and value length are already documented. The description still adds real meaning: the name becomes the {{secret:NAME}} token, allowed_hosts is enforced by refusal rather than merely recorded, and re-calling with an existing name replaces both value and hosts for future attempts.

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?

"Store a credential once and refer to it instead of pasting it into requests" gives a specific verb (store) and resource (a named credential) plus the mechanism that makes it useful. It immediately distinguishes the tool from siblings like list_secrets/delete_secret and from the request-making tools that consume the value.

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?

It names both the alternative it replaces (pasting the literal credential into requests) and the exact consumer tools where the reference is valid (schedule_http, create_cron, watch_http, set_wake), with a concrete header example. An agent knows when to reach for this and when a plain literal value would do.

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