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

Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true, and the description is consistent with all three. It adds real context beyond them: upsert semantics (one secret per key, setting an existing key overwrites its value) and a security trait not encoded anywhere else — values are write-only and never returned by any tool. Auth/permission requirements are the main omission.

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 tight sentences with the core action and resource first, then the upsert rule, then the write-only constraint, then the sibling pointer. No filler and no repetition of the title or schema.

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 an output schema present and all three parameters documented in the schema, the description covers everything an agent needs: what it writes, overwrite behavior, that values can't be read back, and how to make the secret usable. Nothing material is missing for correct invocation.

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%, so the baseline is 3, and the description still adds meaning: the key is unique and re-setting it mutates rather than duplicates, and the value is unrecoverable. Those are behavioral implications the schema's terse field descriptions don't convey.

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 pair and resource ("Create or update a secret") plus a concrete definition of the resource ("an env var, key → value") on an explicit scope (the account). It also disambiguates the create-vs-update behavior in the same breath, which an agent can use to tell it apart from attach_secret, list_secrets, and delete_secret.

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 routes the follow-up step: "Use attach_secret to bind it to a server or project," which is the main ambiguity an agent would have with a sibling named attach_secret. It doesn't address when to prefer delete_secret or list_secrets, but the create/update vs bind distinction is the one that matters for correct selection.

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