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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the safety profile is covered by structured data. The description confirms the write nature and that it only appends (no removal), which adds a bit beyond annotations, but gives no info on duplicate handling, limits, or partial-failure behavior.

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 short sentences with the operation type front-loaded ('WRITE:') followed by scope and endpoint. Every clause carries information and nothing is wasted.

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 3-parameter write tool with no output schema and full annotation coverage, the description gives enough to invoke it correctly. Missing only minor behavioral detail such as append-vs-deduplicate semantics and what the response returns, which the schema and annotations can't fully supply.

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 all three parameters (uuid, coupon_group_id, coupons) are already well documented, including cross-references to sibling list tools. The description adds no parameter-level detail beyond the schema, 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 ('add coupon codes to an existing coupon group') and immediately distinguishes itself from creating a group with 'existing'. An agent can tell it apart from referralhero_create_coupon_group 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?

'It only adds codes' clearly signals this is an append operation, not a create-group or replace operation, which routes the agent away from create_coupon_group. However, it never states when to use this versus other coupon tools or names any prerequisites/alternatives explicitly.

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