Record a rule

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

Goes beyond annotations by describing side effects: 'appends and never edits existing rules, so calling it twice records the rule twice.' Also discloses error conditions when the project or Rules note is missing.

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?

Four sentences pack purpose, definition, alternative guidance, and error behavior without redundancy. Every sentence earns its place.

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?

Complete for a write tool with 3 required params, no output schema, and no annotations beyond safety hints. Covers concept, side effects, duplicate-call consequence, error conditions, and sibling differentiation.

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 covers 100% of parameters, but the description enriches the meaning of 'rule' by defining it as 'standing constraints the operator has confirmed' and contrasting with observations. This adds context beyond the schema's basic field descriptions.

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 states a specific verb and resource: 'Add a durable rule to a project's Rules note.' It distinguishes from siblings by contrasting with 'append_decision' and 'update_capsule', clearly defining what qualifies as a rule.

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?

Explicitly provides when to use alternatives: 'Use `append_decision` instead for a choice that was made, and `update_capsule` when the summary itself is now wrong.' Also clarifies what counts as a rule versus a one-time observation.

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