wait_for_any_of

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

With no annotations and no output schema, the description carries the full behavioral burden and largely delivers: it discloses the race semantics, the success return (index + kind + value), and the timeout contract (returns 'timeout' rather than throwing). It omits edge cases like invalid selector strings or malformed conditions, but the core runtime behavior is transparent.

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?

Four sentences, each earning its place: differentiator, condition shape, return contract, and a vivid example. The racing concept is front-loaded, and the 'Stay signed in? / Skip for now / inbox' example conveys the branching use case with zero waste and no repetition of schema content.

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?

For a 2-parameter tool with no output schema and no annotations, the description covers behavior, condition format, return values for both outcomes, and a usage scenario — near-complete. Minor gaps: 'index' is never explicitly defined as the position in the conditions array, and error behavior for invalid condition kinds is 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% — timeout is documented as 'Max wait in ms' and conditions as 'Conditions to race. First match wins.' — so the baseline is 3. The description does add the condition object shape and the concrete enum values, but the schema already encodes the kind enum, and the added return-format detail pertains to output rather than parameter meanings. Net value over the schema is modest.

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 opens with a specific verb-resource combination — 'Race multiple wait conditions' — and immediately sets it apart from single-condition wait siblings (wait_for, wait_for_url) via the racing and first-match-wins semantics. The stated purpose ('so the agent can branch immediately without sequential probes') makes the tool's role unambiguous.

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?

Provides clear, concrete context with a named scenario: 'Ideal for post-login flows where the next page could be any of several.' It implicitly contrasts with sequential probing but never names a specific alternative tool or states when NOT to use it, so the guidance is context-rich but stops short of explicit exclusion routing.

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