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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the description's contribution is the 'verified' quality signal and Canadian geographic scope, which are genuine additions. It stops short of describing result volume, ordering, or what 'featured' means operationally.

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?

A single front-loaded sentence with no filler; scope, resource, and included domains are packed into one line without redundancy.

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-optional-parameter read-only tool with full schema coverage and no output schema, the definition is serviceable but leaves two gaps an agent needs: the meaning of 'featured' relative to list_all_referral_codes, and the category vocabulary inconsistency with the schema.

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?

The description lists categories as 'banking, internet, telecom, cashback, lifestyle,' but the schema enumerates 'banking, internet, cashback, lifestyle, tools, shopping, gaming' — 'telecom' is described but absent from the schema, and three schema categories are omitted. This mismatch actively risks misdirecting the agent, though the schema itself is fully documented.

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+resource: 'List verified Canadian consumer referral codes and sign-up bonuses,' with parenthetical domains that scope the offering. The word 'consumer' implicitly separates it from the business-oriented sibling, though the distinctive term 'featured' from the tool name is never explained.

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?

No when-to-use guidance is given and no alternative is named, even though siblings like list_all_referral_codes and search_referral_codes clearly overlap in surface area. It also never explains what qualifies a code as 'featured' or 'verified,' which is exactly the selection criterion an agent would need.

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