Build campaign-plan shell

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

Annotations cover the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=false), and the description adds non-obvious behavior: it writes a markdown file under data/campaigns/, returns the plan id plus shell text, and rejects unscored offers with an error that names them. It does not state what happens on repeat calls (overwrite vs. duplicate) despite idempotentHint=false, which is the one remaining 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 sentences, front-loaded with what is produced, followed by the precondition and the sibling routing. Every clause carries information; no filler.

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?

No output schema exists, but the description compensates by stating the return values (plan id plus shell text) and the side effect (markdown file location). Combined with the 100%-covered input schema and annotations, an agent has everything needed to invoke it correctly.

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 both parameters are already documented in the schema; the description mostly restates that offers come from score_offer. It adds no format or matching detail beyond the schema's 'exact text match' note, so the baseline 3 is appropriate.

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 (build) and resource (campaign-plan shell) and enumerates the four artifacts produced: strategy stubs, channel briefs, numbered offer registry, scoring appendix. It explicitly distinguishes itself from the sibling check_plan ('this creates the shell; check_plan later validates everything written against it').

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 an explicit precondition ('Do NOT call it before each offer has a score_offer'), names the failing behavior when violated, and routes to the alternative sibling check_plan for validation. The when-to-use and when-not-to-use conditions are both stated.

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