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

Annotations already declare this is a non-read-only, non-destructive, non-open-world write, so the description need not restate that. It adds little beyond it: it never mentions the confirmation flow (confirmation_id, confirmation_via) or why an idempotency_key is required despite idempotentHint=false, both of which materially affect how a write must be issued. Nothing is said about replay, retry, or duplicate-record behavior.

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?

One framing sentence followed by three parallel action clauses; the structure is front-loaded and mirrors the discriminator the agent must set first. There is no filler, though the parenthetical field lists are terse enough to feel like schema echoes rather than explanation.

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?

This is a complex write tool with a deep anyOf body, 5 parameters, and no output schema, so the description carries the full explanatory burden. It covers the three body shapes but leaves the confirmation and idempotency mechanics, the required `reason` field, and the success/failure outcome entirely undocumented, which is not enough for an agent to invoke it safely on the first try.

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 only 20%, so the description is the main source of meaning, and it does map the body variants reasonably: event (type, message, task_id), calendar (title, date, all_day), sync-run (repository, run, files, tasks). However it omits the required `reason` field present on two branches and says nothing about project_id, source, idempotency_key, confirmation_id, or confirmation_via, leaving a large share of the five parameters unexplained in prose.

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 names a clear verb ("Record") and enumerates the three record kinds it writes (project event, calendar entry, sync run) with the fields each carries. An agent can tell which branch of the request it is handling without opening the schema. It does not differentiate this tool from any sibling, which keeps it short of 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?

Usage is only implied: the action-to-payload mapping suggests when each branch applies, and "something that happened" hints that this records already-occurred facts rather than planning. There is no explicit when-to-use versus siblings, no note on when the sync-run branch is appropriate, and no guidance on the prerequisites implied by confirmation_id/idempotency_key.

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