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

Beyond the annotations (destructiveHint, idempotentHint, readOnly false), the description discloses a great deal of runtime behavior: blocks appear within minutes, cover the coming 60 days, are private and titled with a specific format, are placed only in the main calendar of the named account, are deduplicated across multiple calendars, follow their event, and are re-placed if removed by hand. This is exactly the kind of context annotations cannot convey.

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 description is a single sprawling, em-dash-laden run-on that is hard to parse and not front-loaded around the primary action. While most clauses carry real information, the structure undermines readability and forces re-reading to extract the core behavior.

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 complex, cross-account, destructive write tool with no output schema, the description covers the effect, lifecycle, scoping, and read-path (busyCopies) well. It omits only secondary details such as permission/auth requirements and any rate-limit behavior.

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 schema already documents every parameter including the boolean on, the into/account addresses, and the provider disambiguators. The description adds little parameter-specific meaning beyond the schema, so the baseline 3 applies.

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 states a specific action — mirroring one account's calendar as busy blocks into another named account, or removing that mirroring. It distinguishes itself from siblings by noting that events_list surfaces blocks under busyCopies and that no tool counts, moves, or cancels a block. The unusual 'Show ... or stop' framing is a bit indirect but the resource and effect are clear.

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 implies the context (make an account's busy time visible in another connected account) and points to calendars_list for the identifiers and events_list for reading blocks. However it never explicitly frames when to choose this over alternatives like free_times_find or circles_free_times_find, so the when-to-use guidance is only implied.

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