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

Discloses two things the annotations do not: the call is synchronous ('Answers at once') and it overwrites every idea not yet launched, which is a genuine side effect. It also states the operation is free, which matters given the sibling credits_get. The overwrite behavior is arguably stronger than destructiveHint=false implies, so the agent would otherwise be under-warned — the description closes that gap.

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?

Three short sentences, purpose first, then cost/latency, then the side effect, then the parameter variant. No filler; every clause carries an operational fact the agent needs.

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 an output schema present the description needn't document return values, and it covers what matters for this 1-param, zero-required tool: cost, timing, where results appear, and the overwrite behavior. Nothing an agent needs in order to call it safely is missing.

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 schema already gives an example, so the baseline is 3. The description exceeds it by explaining the semantic difference between omitting segment (profile-based ideas, which replaces existing ideas) and supplying it ('adds ideas for that audience instead') — a distinction the schema cannot express.

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 ('Suggest campaign ideas') plus the source of truth for the suggestions ('from your company profile'), and names the sibling where results land (campaign_ideas_list). It does not explicitly distinguish itself from campaign_ideas_get/list/launch in a 'this vs that' way, but the generation-vs-retrieval boundary is inferable.

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?

'With segment it adds ideas for that audience instead' gives a clear conditional for the optional parameter, and naming campaign_ideas_list tells the agent where to read results. However, there is no explicit when-to-use statement (e.g. 'call this before launching anything') and no mention of prerequisites or the launch workflow that the 'not launched yet' clause hints at.

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