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

Annotations already declare read-only, idempotent and non-destructive, yet the description still adds real context: auth requirement ('sign-in or an API key'), result ordering ('oldest first'), the per-charge fields returned, the status value set (due, paid, void, refunded), and the online-payment flag. That is substantial disclosure 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?

Front-loaded with the triggering condition, then input, output shape, the sibling exclusion, the follow-up tool, and auth — all in tight declarative fragments with no filler. 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?

No output schema exists, but the description enumerates the returned fields and ordering, plus auth and follow-up routing. An agent has everything needed to call and interpret this one-parameter read tool.

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% and the single parameter is fully documented in the schema (format, pattern, provenance). The description only restates 'Input: the case `id`', adding no new format or sourcing detail, so the baseline 3 applies.

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 ('Returns the charges on a case') and frames it around the user's question ('what they owe on a case or whether a charge is paid'). It explicitly distinguishes itself from the closest sibling, evictions_get_pricing, so an agent can route without opening either 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?

Explicit when-to-use (owing money / charge status), explicit when-not-to-use ('Do not use this for the published prices (use evictions_get_pricing)'), and a named next step ('Next: evictions_get_payment_link for a due charge'). Nothing 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.