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

Annotations already set readOnlyHint=false, destructiveHint=true, openWorldHint=true, and idempotentHint=false. The description goes far beyond these by explaining nuanced behaviors: draft promotion requiring publishing permission, destination expansion semantics, re-aiming delivery via scheduled_at, and the retry behavior for failed destinations. No contradictions with annotations; it adds substantial context.

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 front-loaded with the core purpose in the first sentence, but it is a dense wall of text. While every sentence carries important information, the lack of bullet points or paragraph breaks reduces scannability. It is appropriately sized for the complexity but could be more structured for easier parsing.

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?

Given six parameters and complex behaviors (draft promotion, destination expansion, retry logic, post-publication restrictions), the description covers all operational scenarios comprehensively. The presence of an output schema means return values need not be described, and nothing an agent needs to correctly invoke the tool 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%, yet the description adds meaningful semantics beyond each field's basic definition. For example, it clarifies that groups are expanded immediately (not live-linked), that account_ids replace the entire destination list, and that scheduled_at in the past sends as soon as possible. This enriches the agent's understanding of parameter interactions.

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 clearly states the tool's purpose: 'Change a post that has not gone out yet: its caption, its time, its destinations, or whether it is a draft.' This is specific and distinguishes it from siblings like posts_cancel (cancel) and posts_schedule (schedule new), making selection unambiguous.

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?

Provides explicit guidance on when and how to use the tool: it explains that editing is always allowed but sending a draft requires publishing enabled, and that caption/destinations can only be changed before anything publishes. It also details how to retry failed destinations, covering exclusion criteria and alternative behaviors without needing to reference sibling tools.

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