register

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

Annotations already declare idempotentHint and non-destructive, but the description adds the concrete consequence — an existing actor is returned unchanged with created=false — plus the non-obvious rule that display_name is ignored on re-registration. That last point is real behavioral value the annotations cannot express; only the return-value detail is somewhat redundant with the output schema.

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?

Three short sentences, each carrying a distinct load: purpose, when to use, and behavior of the two parameters. The core action and its precondition are front-loaded before the edge-case rules.

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 two-parameter registration tool with an output schema, nothing an agent needs is missing: what it creates, the id format, idempotent re-call behavior, and when display_name is applied. Return shape is deliberately left to the output schema.

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 0% and the schema has no pattern or enum, yet the description supplies the critical format constraint that `id` must begin with 'human:' or 'agent:' (with a concrete example) and explains when display_name actually takes effect. Both parameters gain meaning that exists nowhere in the structured fields.

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?

"Register an actor without writing an idea" gives a specific verb plus resource and immediately separates the tool from the idea-writing path (capture-like siblings). The clause about passing a person as `originator` pins down the exact entity being created (an actor record), so an agent can identify it without opening the schema.

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 states a precise precondition: use it before passing a person as `originator` when that person has never written anything themselves. The idempotency note also implicitly tells the agent it does not need to check for existence first, which removes a common wrong call sequence.

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