echo.ping

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

No annotations are provided, so the description carries the full burden. It discloses that the tool does not hit the network, mutate vault state, or charge, and that it is idempotent except for an audit-ledger append. This gives an agent a clear behavioral safety profile without needing structured annotations.

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 compact and front-loaded with purpose, followed by usage guidance, side-effect transparency, and a sibling distinction. Every sentence earns its place and there is no redundant prose.

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 single-optional-parameter tool with no output schema, the description is complete: it explains what is echoed, what authentication context is returned, when to use it, and what side effects to expect. An agent has enough context to invoke 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?

There is only one optional parameter, message, and schema description coverage is 100%. The schema already explains that the message is echoed back and that omitting it sends an empty ping, so the description adds little beyond what the schema provides.

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 'Identity probe' and states precisely what the tool does: echoes call arguments and the authenticated Principal. It also distinguishes itself from the sibling context.inspect with the explicit 'Not a substitute for context.inspect' note, so an agent can tell them apart.

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 gives an explicit use case: 'Use it to confirm Bearer identity survived onto the tool worker.' It also provides a clear when-not-to-use signal by stating it is not a substitute for context.inspect, naming the relevant alternative.

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