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

With no annotations, the description carries full responsibility for behavioral disclosure. It states that the value is never echoed back, that it merges without touching other fields, and details the authentication proof requirements (nsec-signed kind-27235 or cached dpop_token) and rejection of patron proofs. This is strong coverage for a mutation tool.

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?

The description is concise yet information-dense, with each sentence adding distinct value: purpose, merge semantics, usage example with caution, no-echo guarantee, and auth restriction. It is front-loaded with the primary action and avoids redundant restatement of the tool 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 mutation tool with security constraints, the description covers purpose, when to use, behavioral guarantees, and authentication requirements. It distinguishes itself from sibling tools (operator vs patron, field-level vs bundle) and relies on the existing output schema for return details. Nothing critical is missing for an agent to call it correctly.

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 parameters are already documented. The description adds a concrete example (btcpay_api_key) and clarifies the semantic of 'field' as a single credential field within the operator's template. It also ties the dpop_token to the proof requirement, adding context beyond the schema's generic 'Operator proof for this tool'.

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?

The description opens with a specific verb-resource pair, 'Add or update a single operator secret field', and immediately clarifies its scope as the field-level counterpart to whole-bundle delivery. It also explicitly distinguishes operator from patron credentials, making it unambiguous among siblings.

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 gives a concrete use case (rotating one secret like a reissued btcpay_api_key) and explains when not to use it (patron proofs rejected, and the contrast with re-delivering the whole bundle where omitted fields are destroyed). It does not name the exact sibling tool (e.g., goodearth_update_patron_credential) but clearly implies the operator-only scope.

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