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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds the scope constraint (one provider, user's calendar, bounded date range) but says nothing about prerequisites such as the calendar needing to be connected, or how busy blocks are aggregated.

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?

A single compact sentence with no filler, and the distinguishing scoping qualifier is placed at the end of the sentence rather than buried. Efficient, though it leaves room for one more sentence of routing guidance without becoming bloated.

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?

There is no output schema, but the description tells the agent the return is 'free/busy blocks' within a date range, which is enough to understand the shape of the result. Combined with fully-covering read-only annotations and a mostly documented schema, the only real gap is the unexplained timeZone parameter.

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 75%, with descriptions for 'from', 'to', and 'calendar'. The description only restates those semantics ('date range', 'one provider') and adds nothing for the undocumented 'timeZone' parameter, which is the one field an agent would most benefit from having explained. Baseline 3 is appropriate given the schema does most of the work.

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 ('Get') and resource ('the free/busy blocks of the user's calendar'), plus the scoping qualifier 'of one provider in a date range'. It is clear what the tool does, but it does not differentiate from closely related siblings such as get_busy_times, get_connection_freebusy, or get_user_availability.

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 by the phrase 'of the user's calendar of one provider' – an agent can infer this is the per-provider free/busy variant, but no explicit when-to-use or when-not guidance is given. The crowded sibling set (get_busy_times, get_connection_freebusy, get_team_availability) makes an explicit routing sentence the most valuable thing missing here.

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