calendar_focus_time

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

With zero annotations the description carries the full burden and does so well: it discloses the outward-facing effect (colleagues see the block), the auto-decline side effect, the confirm requirement, and the important lifecycle quirk that the block is not visible in the calendar provider and must be read back from the app / removed via calendar.delete_special.

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 short, front-loaded sentences with no filler; the core purpose leads and the lifecycle caveat follows. Efficient, though the parenthetical clauses could be tightened.

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 an eight-parameter mutation with no annotations and no output schema, it covers the essential behaviors (outward-facing impact, confirm gate, non-provider lifecycle). It leaves minor gaps such as what the returned block looks like and how decline/message interact, but nothing critical to correct invocation is missing.

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 all eight parameters including the decline enum are already documented in-schema. The description only obliquely reinforces auto_decline/decline via 'meetings can be auto-declined' and adds no syntax or default detail beyond the schema, so 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?

States a specific verb+resource ("Create a Focus time block in the Calendar app") and adds scope detail (colleagues see it, meetings can be auto-declined). The 'not in the calendar provider' line separates it from provider-level tools, though it never explicitly contrasts with calendar_create/calendar_update.

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?

Conveys the use case (blocking focus time) and a precondition (confirm=true), but never states when to prefer this over calendar_create or calendar_update for a normal event, nor when not to use it. Guidance is implied rather than explicit.

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