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

The annotations already indicate readOnlyHint=false and openWorldHint=true, so the mutating/external nature is covered. The description adds no further behavioral context such as immediate visibility, auth requirements, failure behavior, or effects on the original post, providing minimal value beyond the annotations.

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 two short sentences with no filler. The action is front-loaded and the usage condition immediately follows, so every sentence earns its place.

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 two-parameter tool with a fully documented schema and no output schema, the description names the action, target platforms, and invocation trigger. Nothing essential for an agent to select and call the tool correctly 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 description coverage is 100%: both postId and platform have descriptions, and platform has a clear enum. The description only mirrors the schema's platform names without adding extra parameter meaning, so a 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?

The description states a specific verb ('Publish'), resource ('a post as a story'), and platform scope ('Facebook or Instagram'). The phrase 'as a story' clearly distinguishes this from publish_post and other content tools in the sibling list, and the use-case sentence reinforces the exact purpose.

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?

'Use this when the user wants to post an Instagram/Facebook story' explicitly states the trigger condition. It does not name alternative tools or exclusions, but the context is clear enough for an agent to know when to select it.

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