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

With no annotations provided, the description carries full behavioral burden. It discloses that this is a human-in-the-loop flow, that the recipient must manually reply, and that each receive_credentials call destructively drains the relay mailbox. These are non-obvious behavioral traits that an agent needs to know before invoking the 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 front-loaded with the core purpose and each paragraph adds distinct value: purpose, alternative use cases, human-in-the-loop flow, and post-call guardrails. It is somewhat long for a tool description, but the extra length is justified by the multi-step credential-delivery workflow and destructive receive_credentials behavior.

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?

Given the tool's complexity and lack of annotations, the description is complete enough for an agent to call it correctly. It covers the purpose, when to use it, the human workflow, the expected next step, and the destructive consequence of pollng receive_credentials. An output schema also exists to explain return values, so no critical information 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 description coverage is 100%, so the baseline is 3. The parameter descriptions in the schema already explain service as a credential service name and sender_npub as the target npub. The tool description adds some contextual value by indicating the secret-delivery nature, but does not materially expand parameter semantics beyond the schema.

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 states a specific action: open a Secure Courier channel for credential delivery, hand over service secrets (API keys, tokens), and sends a welcome DM with a credential template. It explicitly distinguishes itself from request_npub_proof, so the agent can clearly identify which tool to use for this flow.

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?

The description provides explicit when-to-use guidance: use for CREDENTIAL-DELIVERY of service secrets, use request_npub_proof instead for merely proving npub control, and check service_status first for dynamic/OAuth2 services. It also gives post-call workflow instructions: STOP, wait for user confimation, then call receive_credentials, and do not poll or retry.

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