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

Annotations already declare a non-destructive, non-idempotent write, so the bar is lower. The description adds genuinely non-obvious behavior: media is referenced rather than re-uploaded and quota is not charged twice, which materially affects an agent's decision. It does not say whether the draft is auto-scheduled or what happens if the source media is later deleted.

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 core action is front-loaded in the first sentence, with behavior and parameter notes following in a logical order. The title line 'Convert a post or video into a Story' slightly restates the opening sentence, a small redundancy.

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 mutation tool with no output schema, the description covers what is created (a draft) and quota behavior but says nothing about the returned object, whether the draft must be published separately via publishStory, or permission requirements on the source post. Adequate but with clear gaps for correct downstream use.

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 50%, and the description does add value by mapping 'source' to the generated_posts/video_posts tables. However, postId and platforms remain undocumented in both schema and description, and the caption fallback rule in the schema already covers that parameter, so the description only partially compensates for the coverage gap.

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 definition gives a specific verb and resource ('Convert a post or video into a Story draft') and clarifies that source media is reused rather than re-uploaded, which implicitly separates it from createStory/createVideo. It stops short of naming those siblings explicitly, so an agent must infer the boundary.

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?

Usage is only implied: the quota explanation and the 'source' hint suggest this is the right tool when media already exists in a post or video, but there is no explicit 'use this instead of createStory when...' guidance or prerequisite statement. The only direct instruction concerns the source parameter, which is parameter-level rather than tool-selection guidance.

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