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

Annotations declare a non-read-only, non-idempotent, non-destructive write, and the description adds the substantive constraints behind that: the one-flow-per-campaign precondition, the fact it cannot be re-run, and that post-creation edits must go through `flow_set`. That is real behavioral context beyond the annotation flags.

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-loads what it does and its key precondition, then spends the remaining sentences on routing and the placeholder rule. The 'one of three ways' comparison is compact and each clause carries distinct information; nothing is padding.

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?

Covers purpose, preconditions, alternatives, and the conditional placeholder rule, which is enough to invoke it correctly. The only omission is what the call returns (e.g., the created flow id) — minor, but with no output schema there is nothing else to fall back on.

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%, so the baseline would be 3, but the description supplies the conditional requirement the schema cannot express: which of longNote/shortNote/message1..3/subject1..3/content1..3 apply is determined by the chosen template. It also clarifies that `sequence` is a library name, not an id.

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 ('Attach one of the platform's named sequence templates to a campaign') plus the side effect ('fill in its copy placeholders'). It explicitly distinguishes itself from `flow_set` and `campaign_generate_ai_sequence`, so an agent can pick it out of a large sibling set without opening a 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?

Gives explicit when-to-use (reuse a prebuilt shape), when-not-to-use (campaign already has a flow; cannot be re-run), and named alternatives for both other paths (`flow_set`, `campaign_generate_ai_sequence`). It also prescribes the ordering dependency: call `template_list` first because the name is matched against that library.

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