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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely useful context beyond them: 'No sign-in', 'This does not change the plan', and the per-user pricing semantics that prevent misquoting. It stops short of describing response shape nuances like currency handling.

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 core purpose and reasonably tight, though several short sentences (sign-in, plan mutation, channel_packs) read as a checklist. Each sentence carries information, but the channel_packs detail is slightly ahead of need for a single-parameter listing call.

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?

With no output schema, the description usefully sketches the return shape (per-user monthly figures and channel_packs contents), which is exactly what an agent needs. It omits currency behavior in the result, a minor gap for a tool this simple.

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 single currency parameter is fully documented with enum and default in the schema. The description adds no meaning beyond that, so the baseline of 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 ('List Free, Pro, and Business monthly prices') and names related data (channel_packs). Clearly distinguishable from sibling quote tools like quote_service or explain_charges.

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 operational guidance on how to present the result ('Quote that amount. Do not round it...') but never says when to use this tool versus alternatives such as quote_service, quote_number, or explain_charges. Usage is implied rather than routed.

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