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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the safety profile is covered. The description adds genuine behavioral context beyond that: the fallback when the provider doesn't sell the bill (provider_note plus a general script), which is output behavior an agent cannot get from 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-loads purpose and then lists representative intents, which is efficient for intent matching. The opening 'Lower My Bill. A call script to lower a bill.' partially duplicates the name and title, a minor waste, but the remainder 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?

Read-only tool with no output schema, so the description carries output-shape detail but doesn't need to explain return values extensively. It covers the bill/provider combination and the fallback path, though it never states what happens when no argument is supplied, despite zero required parameters.

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 every parameter is already documented in the schema (bill types, state programmes, country effects, provider examples). The description only restates the 'bill, provider, or both' combination rule and adds no new syntax or constraint, 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?

The description states a specific verb and resource: it produces a call script to lower a named bill, and the example prompts ('help me lower my Comcast bill', 'lower my Council Tax') make the resource scope concrete. It does not, however, distinguish itself from the sibling lowermybill_get_bill_help or lowermybill_get_call_reminder, so agent routing between them relies on inference.

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?

It gives real routing signal by listing example intents and saying to supply 'the bill type, the provider, or both'. But it never states when to prefer this tool over lowermybill_get_bill_help or lowermybill_get_call_reminder, so usage is implied rather than explicit.

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