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

With no annotations supplied, the description fully discloses the human-in-the-loop behavior, DM/template mechanics, the need to wait for user confirmation, and the destructive-drain warning on receive_credentials. This goes well beyond a simple action statement and provides operationally critical side-effect context.

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 longer than average but every section earns its place: purpose, sibling differentiation, OAuth exception, workflow, and anti-polling warning. The most important decision information is front-loaded before the step-by-step flow.

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?

The tool has an output schema, so return values do not need elaboration. The description covers selection criteria, important exclusions, the human-in-the-loop procedure, and cross-tool coordination with receive_credentials, making it complete for an agent to invoke and proceed 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 description coverage is 100%, so the parameters are already documented in the input schema; the description does not need to compensate. It neither adds nor obscures parameter meaning beyond referring to services and npubs, so baseline 3 is appropriate.

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?

Description states a specific action and object: 'Open a Secure Courier channel for credential delivery' and explains it is for handing over service secrets (API keys, tokens). It explicitly separates this from request_npub_proof, so an agent can identify the tool's niche among its many authority_* 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?

Provides direct when-to-use guidance ('use it to hand over a service secret'), names the alternative for npub proof, and adds an exclusion for OAuth2/dynamic services with a pointer to service_status. It also specifies the post-call workflow: stop, tell user, wait, and do not poll.

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