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

Annotations already declare readOnlyHint/openWorldHint, so the safety profile is covered. The description adds real behavioral context beyond that: pagination mechanics ('Pages hold up to 50 events; pass next_cursor back as cursor'), the scope constraint ('events you host'), and an auth prerequisite (Cotlet API key with access to this app). Rate limits and ordering are not stated, keeping it short of a 5.

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-loads the tool's scope and return shape, then trails into chaining, pagination and auth. Every sentence carries information and none is filler, though the density makes it slightly longer than a minimal list description needs to be.

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 no output schema, the description usefully describes the return payload (start time, canceled flag, RSVP counts) and covers pagination and auth for a read-only list tool. It is essentially complete, though ordering/default sort behavior is left unstated.

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 description coverage is 100%, so when/limit/cursor are already documented including the 1-50 limit range and the enum values. The description repeats the page size and cursor flow rather than adding new syntax or defaults, 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?

States a specific verb and resource ('Events you host') and immediately enumerates the returned fields (date, status, guest counts), which clearly separates it from siblings like partiful_get_event or partiful_list_guests. An agent can identify the tool without opening the schema.

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?

It gives a chaining hint ('Use event_id from each item in the other tools'), which implies this is the entry point for the Partiful toolset. However, it never states when to prefer it over alternatives such as partiful_list_past_guests or partiful_get_event, and no exclusions are given. Usage is implied rather than spelled out.

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