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

Annotations cover read-only/open-world, but the description adds far more: the incomplete-success contract for ok:true/complete:false, coverage.unknown_minutes and unknown_windows[], the rule that unknown windows are omitted rather than assumed free, horizon.effective_to clamping semantics, and explicit 'NO TOKEN REQUIRED' auth disclosure. This is exactly the extra behavioral context annotations cannot carry.

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?

Front-loaded with the two facts an agent needs first (slots + policy together, then the read-order rule). The return-shape enumeration and the negotiation metaphor add length; the metaphor sentence is stylistic rather than informational, but the rest of the length is earned by genuinely non-obvious semantics.

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?

No output schema exists, yet the description enumerates the full response shape (ok, complete, member, meeting_type fields, slots, coverage, unknown_windows, horizon, generated_at), explains the empty/incomplete cases, and discloses auth requirements. An agent could call and interpret this correctly without further probing.

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 baseline is 3, but the description reinforces semantics the schema states and adds cross-parameter meaning: start/end are UTC ISO-8601 with trailing Z, member.tz and viewer_tz are IANA zones and wall-clock arithmetic is forbidden without one, and the arg list is restated. Useful but largely overlapping with the schema.

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 (open slots for one meeting type) and an unusual scope addition (the member's full booking policy in the same response). It is clearly distinguishable from ic_scheduling_list_meeting_types, which it references as the source of the meeting_type slug, and from ic_scheduling_manage_booking.

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?

Gives strong when-to-use guidance: read the policy block before the slots, understand that complete:false is an incomplete success, and that empty slots with complete:true means genuinely booked. It routes to ic_scheduling_list_meeting_types for the slug, but does not explicitly contrast against ic_scheduling_manage_booking or state when not to call this.

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