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

Goes well beyond the destructive/idempotent annotations: discloses that media_file_ids and account_ids replace the entire list, that the change is atomic ('nothing is changed' if any platform fails validation), and enumerates what cannot be modified. This is exactly the mutation-risk context an agent needs before a destructive call.

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?

Front-loaded with the scope and the editable fields, then consequences, then exclusions — no filler sentences. Slightly dense run-on phrasing, but every clause carries operational meaning.

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 7-parameter destructive mutation with no output schema, the description supplies preconditions (read first), atomicity, list-replacement hazards, and the unsupported-field workaround. Nothing an agent needs to call it safely 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 coverage is 86% and the schema already documents the replace semantics and timezone handling, so much of the description restates structured data. It still adds real value by tying replace behavior to a required read step and by grouping the editable fields, which helps an agent avoid data loss.

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 and resource (changes a post) and scopes it precisely to SCHEDULED posts and DRAFTs, plus the editable fields. This immediately separates it from siblings like update_plan_post, publish_draft and cancel_post.

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?

Explicitly instructs to read the post with get_post first, tells the agent that a draft takes no time and that publish_draft supplies one, and names the escape hatch (cancel and create again) when platform options or a TikTok account must change.

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