set_plan

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

Annotations already declare it is a non-read-only, non-open-world, non-destructive mutation. The description adds two pieces of behavior the annotations do not: that the plan is fully replaced ("Overwrites the plan") and that the call returns the get_plan result. That overwrite semantics is exactly the kind of side effect an agent needs before calling. It could still say more about what happens to unspecified fields or default persistence.

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 terse sentences with zero filler, and the core action is front-loaded ahead of the overwrite caveat and the return-value note. Nothing redundant.

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 4-parameter mutation with no output schema, the description covers the action, the overwrite side effect, and the returned payload (get_plan), which is enough for correct invocation. It stops short of describing default behavior for omitted parameters, which is left to the schema.

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%, with each of days, time, weeks and platforms documented inline including defaults and ranges, so the schema carries the load. The description adds only the loose phrase "posting days the user picked," which does not clarify parameter syntax beyond the schema. Baseline 3 is appropriate.

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 pairs a specific verb ("Save") with a specific resource (the posting days / the plan) and implicitly distinguishes itself from get_plan by naming it as the return target. It does not, however, differentiate itself from nearby siblings like set_post or get_plan in scope terms beyond the one-word resource.

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?

There is no statement of when to reach for this tool versus the sibling get_plan, or versus other plan-affecting tools. The only implicit signal is that days must have already been picked by the user, which an agent has to infer from "the user picked".

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