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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the description is free to add the operationally interesting traits: stop-over matching semantics, Pacific timezone, price inclusive of fees, and the explicit constraint that booking cannot happen here. Nothing contradicts the annotations.

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 purpose and invocation inputs, then returns, then the booking caveat. The parenthetical "(the same link request_ride_link gives)" is redundant, and the second paragraph is dense, but every other sentence carries information.

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, so the description correctly carries the return-value burden (route, departure time zone, seats left, all-in USD price, driver first name, booking link). Combined with date handling and the no-result fallback, an agent has everything needed to call and interpret this tool.

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 adds real matching semantics beyond the schema: that a ride stopping in a city counts for that city ("a San Jose to San Diego ride with a Los Angeles stop is found for Los Angeles to San Diego"), which directly affects how from/to values are interpreted.

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?

Opens with a specific verb and resource ("Find upcoming long-distance carpool rides on Seat Sherpa") and scopes the domain to California and Nevada. It also implicitly separates itself from siblings by noting it returns a list and cannot book, unlike get_ride or post_ride_link.

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 invocation context (supply from/to city or place names, optional travel date) and handles the no-results case by routing to request_ride_link. It does not, however, explain when to prefer get_ride or list_service_areas over this search, so sibling differentiation is only partial.

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