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

With no annotations provided, the description carries full responsibility for disclosing side effects. It does state the critical guarantee 'without creating anything', which signals safe, non-mutating behavior. Yet it does not describe other behavioral aspects such as whether it validates the schedule, performs network calls, or has rate limits. The coverage is minimal but not misleading.

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?

The description is a single, tightly constructed sentence that packs the core purpose, the expansion outcome, and the side-effect-free guarantee. It is front-loaded with the action verb 'Preview' and contains no filler or redundant content.

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 preview tool with one nested parameter and no output schema, the description gives a clear high-level idea of the output ('concrete posts and steps'). It lacks specific return format details, but the schema's parameter documentation compensates for input complexity. Considering sibling tools and the overall simplicity, this is reasonably complete, though not exhaustive.

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 input schema already provides a highly detailed description of the 'schedule' parameter, including minimal shape, campaign document variants, and provider-specific settings. Since schema description coverage is 100%, the tool description itself adds no extra parameter semantics. The baseline of 3 applies because the schema does the heavy lifting.

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?

The description uses a specific verb 'Preview' and clearly identifies the resource ('campaign schedule document') and the outcome ('expands into concrete posts and steps'). It also explicitly states a key differentiator: 'without creating anything', distinguishing it from apply_schedule and publish_draft. This makes the tool's purpose unmistakable and distinct from siblings.

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?

The phrase 'without creating anything' strongly implies a read-only, exploratory use case, indicating you would use this tool when you want to see the expansion before actually applying the schedule. However, it does not explicitly name alternative tools like apply_schedule or validate_schedule, so it leaves room for clearer when-to-use guidance.

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