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

Far beyond the annotations, it discloses that the operation is free (no credits), that there is no duplicate check and calling twice leaves two slots — behavior consistent with idempotentHint=false — and that each call adds exactly one slot. It stops short of describing the response payload, but the output schema covers that.

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 trigger, the negative scoping, and the alternatives are front-loaded, and every paragraph carries actionable content. It runs long at four paragraphs, and the 'spreading a clustered schedule' sentence restates the one-slot-per-call point, but nothing is filler.

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 four-parameter creation tool with full schema coverage, annotations, and an output schema, the description covers everything an agent needs: trigger, exclusions, alternatives, duplicate behavior, prerequisite reads, and account disambiguation. Return values are legitimately left to the output 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 coverage is 100%, so the schema already documents day numbering, HH:MM formatting, and timezone omission. The description adds practical semantics on top: one slot per call so a spread-out schedule needs multiple calls, and the instruction not to pick an accountId on the user's behalf.

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 first sentence states a specific verb and resource — 'creates one smart schedule timeslot on the given day at the given time' — and immediately scopes it to recurring weekly scheduling rather than Pin publishing. It explicitly contrasts itself with create_post and schedule_post, so an agent can route correctly without opening any schema.

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?

It gives an explicit trigger ('when the user wants to add a posting time'), an explicit exclusion ('this does not schedule a Pin'), and named alternatives (create_post or schedule_post with useNextOpenSlot). It also adds prerequisites: read list_timeslots first for existing schedules, and ask the user which account when list_accounts returns multiple.

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