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

Annotations already flag destructiveHint=true and non-idempotent, but the description adds genuinely new behavior: partial-update semantics ('fields left out stay the same') and the side effect that a scheduled post is demoted to draft and must be rescheduled. It still doesn't explain what makes the operation destructive (presumably media replacement/removal) or what the call returns.

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?

Three short sentences: what can be changed, what an omission means, and the scheduling side effect. Front-loaded with the verb and resource, no filler, every clause carries information the agent needs.

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 6-parameter mutation with a nested per-network structure and no output schema, the description covers eligibility, merge semantics and the most surprising side effect. Gaps remain: no statement about what is returned after the edit, and no explicit guidance for replacing or clearing media beyond the schema's own note.

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%, so the baseline is 3, but the description adds meaning the schema does not state: that omitted fields are preserved, making this a merge rather than a replace. It also frames the field groups collectively ('per-network versions or media'), helping the agent map intent to the right parameters.

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?

Names a specific verb (changes) plus the resource (a post) and enumerates the editable facets: text, networks, per-network versions, media. It also scopes the tool to posts in draft, scheduled or failed state, which implicitly separates it from publish_post_now, reschedule_post and create_post without naming them.

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?

The state restriction ('draft, scheduled or failed') tells the agent when this tool is applicable, ruling out editing published posts. The note that a scheduled post reverts to draft is effectively a when-to-use caveat that signals reschedule_post may be the better call for time-only changes, though it never names that sibling explicitly.

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