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

Annotations cover the safety profile (destructiveHint=true, idempotentHint=false), so the bar is lower, and the description still adds real behavioral context: the refusal preconditions and the fact that editing a scheduled story mutates its future public content. It does not say whether unspecified fields are preserved or cleared, which matters for a non-idempotent partial-update tool.

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?

Four short sentences, front-loaded with the core action and with the alternatives placed last where they belong. Slight redundancy between 'Edit an unpublished story' and 'on an unpublished story' keeps it from being maximally tight.

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 10-parameter mutation with nested objects, no output schema, and zero schema descriptions, the description covers preconditions, side effects, and routing well but leaves the parameter-level contract largely undocumented. An agent can still call it, but cannot confidently predict partial-update semantics or field interactions.

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 0% across 10 parameters, so the description carries the full burden, yet it only groups fields into 'caption, media, and destinations' without adding meaning beyond the property names. Duration, mediaFit enum values, thumbnailUrl behavior, and the relationship between platforms and facebookTarget/tiktokSettings are all left unexplained.

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?

Specific verb (Edit) plus resource (unpublished story), and it enumerates the editable surface: caption, media, destinations. It also distinguishes itself from siblings by naming scheduleStory and cancelSchedule as the timing tools, so an agent can route without opening the schemas.

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?

Explicit when-to-use (unpublished stories), explicit when-not (refuses active, partially published, or already posted stories), and explicit alternatives for a related need (scheduleStory / cancelSchedule for timing). It also states the boundary condition 'edits do not publish', which is exactly the kind of routing rule an agent needs.

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