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

Beyond the annotations (destructiveHint=true, idempotentHint=true), the description adds real behavioral context: partial-update semantics, zero credit cost, non-publishing behavior, and the important side effect that changing the day of an already-queued post also alters its external publishing schedule. That last sentence explains the destructive hint rather than contradicting it. It still does not say whether any post state blocks editing or what errors occur.

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 tight sentences with the scope statement first, then the partial-update contract, then cost/publish behavior, then the schedule side effect. Every clause carries information; the long field enumeration is dense but purposeful rather than padded.

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 16-parameter mutation with no output schema and only half the params schema-documented, the description covers the essentials an agent needs: what is mutable, that unspecified fields are preserved, that it costs nothing, that it does not publish, and the one non-obvious cascading effect. Remaining gaps (permission/auth requirements, valid state preconditions, behavior when platform changes) are modest but real.

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 50% across 16 parameters, so the description needs to compensate and largely does not. It names the editable field families (hook, caption, CTA, hashtags, pillar, goal, visual direction, platform, format, day, status) which helps map intent to parameters, but adds no semantics for the eight undocumented params (cta, goal, hook, format, pillar, status, platform, visual_direction).

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 opens with a specific verb ("Change") and resource ("a planned post") and then enumerates exactly which fields can be edited, mapping directly onto the schema's properties. It is unambiguous about what the tool does, but it never differentiates itself from close siblings such as reschedule_social_post or delete_social_post, which is the only gap keeping it from a 5.

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?

"Only the fields you pass change" and "Free; this does not publish immediately" give useful preconditions for invoking it (partial update, no credit cost, no publish side effect). However, no alternative is ever named, so an agent that wants to move a post's date has no signal about whether to call this tool or reschedule_social_post; usage must be inferred.

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