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

Adds real context beyond the annotations: rules cannot be mutated here (only in the dashboard), matching ignores http/https and trailing slashes, and linked URLs inherit their base URL's rule. It also warns against client-side URL matching, which is a genuine behavioral pitfall. Minor gap: no note on result size or ordering, though the output schema covers shape.

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 trigger condition, then contents, then a domain definition, then the sibling alternative, then operational constraints. Every sentence carries distinct information; nothing is redundant padding.

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-parameter read-only tool with a full output schema and rich annotations, the description covers triggers, alternatives, domain semantics, mutation limits, and account disambiguation. Nothing an agent needs to call it correctly is missing.

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 100% and the accountId description already points at list_accounts, so baseline is 3. The description goes further by mandating that the agent ask the user which account to use when multiple accounts exist rather than guessing, which is meaningful semantics the schema does not convey.

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 and resource (lists the account-wide default rule, URL-specific custom rules, and linked URLs) and explicitly distinguishes itself from the sibling get_pin_spacing_rule. An agent can identify what this returns without opening the output 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?

Gives an explicit trigger ('when the user asks what Pin Spacing rules their account has'), a secondary trigger (planning a high-volume schedule across many URLs), and an explicit exclusion routing to get_pin_spacing_rule for single-URL lookups. It also specifies the account-disambiguation protocol before calling.

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