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

The description discloses key behaviors: it replaces previously marked slots within a window and updates the group heat-map immediately. It also explains authentication requirements and the conditional need for a Turnstile token. The annotation readOnlyHint=false is consistent with this write operation.

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 concise (two sentences) and front-loaded with the core purpose. Every sentence adds essential information without redundancy or fluff.

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?

Despite having no output schema, the description explains the impact (replaces slots, updates heat-map) and authentication nuance. It covers the essential context for a tool with 5 parameters and a fallback use case. Minor gap: no mention of what the response looks like or if there's any confirmation.

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?

The schema coverage is 60%, but the description adds meaning to several parameters: windowFrom and windowTo are identified as Unix ms timestamps, freeSlots as an array of objects with start and end, and turnstileToken's requirement is explained conditionally. Email and the structure of freeSlots items beyond start/end are not described, but the description adds value beyond 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?

The description clearly states the verb 'publish' and the resource 'hand-marked FREE time slots for an email address', and distinguishes it as a 'no-calendar fallback' for users like Apple iCloud. This differentiates it from sibling tools such as create_meeting or get_manual_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?

The description provides context on when to use the tool (fallback for non-calendar users) and explains that authenticated callers skip the bot challenge while anonymous callers may need a Turnstile token. However, it does not explicitly state when not to use it or compare it to alternatives beyond the fallback scenario.

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