weekendflights

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

With no annotations, the description carries the full burden and does well: it discloses that it reads already-priced cached data rather than live-searching every destination, that it requires Pro, and that non-Pro callers get a pro_required response with the Anywhere page URL. It stops short of stating cache freshness/staleness or any rate limits, which are the remaining behavioral gaps.

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 sorted-by-price behavior, then caveats and gating. Each sentence is informative, though weekend_prices is referenced twice and the filter-inheritance line slightly overlaps with the fallback line.

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?

Covers behavior, prerequisites, failure mode, and the alternative tool, which is strong for a tool with no annotations and no output schema. The one omission is a hint about the shape of the returned weekend list, which the description only gestures at with 'sorted by price'.

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 all 14 parameters are already documented in the schema, including the month format and defaults. The description adds only that it takes the same filters as weekend_prices, which is routing context rather than new parameter meaning, so the baseline 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 with scope: the cheapest weekends from one origin across every destination with a calendar, sorted by price. It explicitly contrasts with weekend_prices (one route) and the Pro-only 'Anywhere' behavior, so an agent can distinguish it from siblings without opening a 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?

Gives explicit when-to-use and when-not: use this for a whole-origin scan, but if a destination is absent it can be priced with a single weekend_prices call; one route at a time is free with weekend_prices. It also names the Pro-only precondition and the fallback response.

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

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

No annotations, so the description carries the full burden; it discloses the key behavioral trait that results are limited to origins with cached priced calendars and that counts reflect priced destinations. It does not cover cache staleness/refresh behavior or whether the list is exhaustive, so it falls short of full disclosure.

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?

Three short sentences, each earning its place: return shape first, then the routing guidance to each sibling. Nothing is redundant or buried.

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?

No parameters, no output schema, no annotations — the description must and does explain both the returned content (origins plus per-origin counts) and how it relates to the sibling tools, which is everything an agent needs to invoke and interpret it.

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?

Zero parameters, so the baseline of 4 applies; there is no parameter semantics to explain and the description correctly avoids inventing any.

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 and resource ('Returns the departure airports (IATA)') plus precise scope ('that have at least one priced weekend calendar') and the returned payload ('count of priced destinations per origin'). An agent can distinguish this from both siblings without opening any 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?

Explicitly routes the agent: 'Start here to learn what cheapest_weekends can answer at once' names the primary use case, and 'weekend_prices works for any airport pair and searches live when needed' supplies the fallback condition when an origin is not listed. Both alternatives and their selecting conditions are stated rather than inferred.

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

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

With no annotations, the description carries the full burden and does so well: it discloses the cache-first/live-search hybrid ('Cached prices answer at once; weekends not priced yet are searched live during the call'), realistic latency bounds, and a degraded-mode contract ('the answer says which weekends are still open and to call again'). It also states the auth prerequisite (Pro session cookie) for non-default filters. Read-only nature is implicit in a price-query tool and nothing contradicts it.

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?

Three tight sentences that front-load the return shape, then latency/partial-result behavior, then filters and entitlements — a sensible order with little waste. It drifts slightly into restating schema-level filter info, which is the only redundancy.

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 13-parameter, no-output-schema tool, the description covers everything an agent needs: what is returned (cheapest round-trip per weekend + as_of), how long it may take, what happens on timeout, and what credentials unlock which filters. Nothing critical is missing.

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 the schema already documents every parameter's meaning, format, defaults and entitlements; the description only adds a summarizing list ('trip shape, cabin, stops, passengers, departure and return time windows, currency'). That framing is mildly useful but introduces no semantics beyond the schema, so the baseline 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?

Opens with a concrete verb and resource: 'Every weekend of the next 12 months for one origin-destination pair, with the cheapest round-trip price per weekend' — an agent immediately knows this returns a per-weekend price series plus an as_of timestamp. It does not, however, distinguish itself from the sibling 'cheapest_weekends', which sounds like it covers very similar ground, so the agent is left to guess which one to pick.

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 entitlement-based conditions for use: the free tier covers fri-sun/economy/any stops/any passenger mix/no time window, while other combos, cabins and time windows need a Pro session cookie. It also sets latency expectations (10-40 s, at most ~55 s) and tells the agent what to do on a partial result. What's missing is any tie-break against 'cheapest_weekends' — it never says when to prefer a sibling instead.

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