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

Annotations already declare a non-read-only, non-destructive, open-world write, and the description adds substantial context beyond them: the block overrides even pending inquiries/offers, the title is private to the host, the action is effectively irreversible because no unblock call exists, and it requires a Cotlet API key with app access plus a confirmation step. These are exactly the traits an agent needs before invoking a side-effecting tool.

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 core action and effect, and most sentences carry distinct information (scope, title privacy, irreversibility, confirmation, auth). There is mild redundancy around the confirmation requirement ('you confirm each call' / 'confirm with the user before each call'), which slightly dilutes it.

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?

With annotations covering the safety profile and no output schema to explain, the description covers everything needed to call correctly: the mutation's scope, its irreversibility, the guest-visible vs private distinction, the auth/key requirement, and the confirmation policy.

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 start, end, space_id, and title are already documented in the schema, and the description largely restates them (title as a private reminder, guests can't see it). No additional syntax, format, or constraint detail is added over the schema, so the baseline of 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?

Specific verb+resource ('Block dates and times on a space calendar') with the effect stated ('so guests cannot book them'), which lets an agent distinguish it from siblings like peerspace_add_calendar_rate, peerspace_set_instant_book, or peerspace_get_calendar. The scope (blocks for ALL guests, including pending inquiries/offers) further sharpens what this tool does versus adjacent booking tools.

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 clear operational context: it confirms each call by default, requires user confirmation because it 'reaches other people', and notes there is no counterpart unblock call. It does not explicitly contrast when to pick this over siblings that also alter calendar availability, so it stops short of full when/when-not/alternatives guidance.

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