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

Annotations already declare readOnly, idempotent, open-world, non-destructive, so the safety profile is covered. The description adds that results include 'example volumes from live cp0x races,' which hints at data richness, but it does not say how many venues appear, whether results are cached/live, or what the comparison output looks like.

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?

Two sentences, front-loaded with the core comparison, followed by a usage cue. No filler; the only minor opportunity is making the usage sentence a touch more routing-specific.

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 simple read-only comparison tool with no output schema and a fully described single parameter, the description conveys purpose, scope (per-venue or per-category), and data provenance (live cp0x races). An agent can call it correctly, though the return structure remains implicit.

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 there is only one optional parameter, so the schema already documents the category filter fully. The description's phrase 'across a category of venues' reinforces but does not extend the schema's meaning; 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: comparing the benefit a cp0x referral provides versus each venue's own referral offer. It is clearly distinct from siblings like get_referral_code or list_deals, though 'each venue's own referral offer' could be slightly more concrete about output shape.

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 states when to use it: 'when the user wants to know what a cp0x referral code adds on a venue or across a category of venues.' It gives clear intent context but does not name alternative tools (e.g. get_referral_code) for adjacent questions.

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