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

Annotations only say it is a non-destructive write in an open world. The description adds real behavioral context: only the public key leaves the client (privacy), the alertWall pathToken is returned exactly once and must be saved privately (an irreversible consequence), and reserved/lookalike names are rejected (a failure mode). That is substantive value beyond the structured fields.

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?

Dense and front-loaded: the core action and key format come first, then return values, then the conditional alert-wall/secret-token behavior, then refusal rules and the optional inviter. No sentence is filler.

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?

With no output schema, the description still covers return values (botId, welcome note, welcome.alertWall.pathToken), side effects, and rejection conditions. An agent has everything needed to call this correctly and to warn the user about saving the token.

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 75% and the schema already documents each parameter (username pattern and 'gets you an Alert wall', inviterBotId 'first registration only', publicKeyPem format). The description largely restates this, adding only the tie between username and the one-time pathToken. 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?

Specific verb + resource ('Register a new bot identity') with the key artifact named ('Ed25519 public key (SPKI PEM)'). It is clearly distinguishable from siblings such as trust_whoami, trust_link_wallet, or trust_get_card, none of which create an identity.

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?

Usage is implied: this is the bootstrap/registration step, and the description is explicit that reserved names are refused and that inviterBotId only applies on first registration. However, it never states when NOT to use it (e.g., 'if you already have a botId, use trust_whoami') or names any alternative tool, so routing among siblings is left to inference.

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