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: it discloses idempotency (already-absent fields report removed: false without rewriting the vault), the destructive nature ('as destructive as a write'), and precise auth requirements (nsec-signed kind-27235 or cached dpop_token phrase, patron proofs rejected). This is exactly the behavior an agent needs before invoking a restricted mutation.

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-loads the core action, then layers scope, usage, idempotency, and auth in a logical order. Seven sentences is on the long side, but for a restricted destructive tool each sentence adds a distinct, load-bearing fact rather than repeating structured data.

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?

An output schema exists so return values needn't be documented, yet the description still surfaces the removed: false signal. Combined with auth, idempotency, scope, and the sibling distinction, nothing an agent needs to call this correctly 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 the baseline is 3, but the description adds real semantic value by clarifying that 'field' is keyed on what is vaulted rather than what the current template declares, and that it accepts stored-but-untemplated fields. It doesn't add much on dpop_token beyond the schema, keeping it below a 5.

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 ('Remove a single operator secret field', 'Deletes one key from the operator's encrypted credential blob') and immediately distinguishes the scope from the row-level sibling forget_credentials. An agent can tell this apart from delete_patron_credential and update_operator_credential from the text alone.

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 names the alternative ('the field-level counterpart to forget_credentials, which wipes the whole row') and gives concrete when-to-use scenarios (retiring a Prefect key after Modal, a stored-but-untemplated orphan like anthropic_api_key). It also states the key benefit of choosing this over a full re-delivery.

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