create_delegation

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

Goes well beyond the readOnlyHint=false / destructiveHint=false annotations. It discloses billing ('each mint is a billable proof'), a hard failure mode ('a requested lifetime longer than the control proof's remainder is rejected, never truncated'), and the returned shape (publishable token plus DERIVED effective_status/is_valid, consistent with list/get tools).

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?

Front-loaded with the purpose and definition, then progressively adds billing, lifetime behavior, result shape, and access. Every sentence carries information, though the middle section is dense and the access note could be tightened.

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 mutating tool with a nested object parameter, no output schema, and auth requirements, the description covers what is missing elsewhere: return shape, billing implications, the lifetime rejection rule, and the account/API-key prerequisite. An agent has what it needs to decide and call 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 schema already documents all four parameters, including the scope token format and the expires_in remainder constraint. The description adds only marginal parameter meaning ('rejected, never truncated' on lifetime), so the 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?

States a specific verb+resource (create a delegation) and defines what a Proof of Delegation actually is: a control-proven domain authorizing a typed url/purl artifact for capability scopes, returning a publishable signed token. It also scopes the semantics precisely ('the domain's controller authorized this artifact — nothing more'), which lets an agent distinguish it from sibling verbs like list_delegations, get_delegation, and verify_delegation.

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 a clear prerequisite in the ACCESS section (needs a Proof account, set PROOF_API_KEY, restart) and an explicit when-not: 'start_login does NOT open this tool.' What is missing is any routing versus close siblings such as create_authorization or create_confirmation, which an agent might otherwise confuse with this minting operation.

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