Reno Car Fix — book mobile mechanic in Reno

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

Annotations already declare readOnlyHint, openWorldHint=false, and idempotentHint, so safety is covered. The description adds real value beyond them by disclosing the return content (yes/no and the nearest served town) and by scoping the operation to the Reno area only, which matters given openWorldHint=false.

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?

Two compact sentences, front-loaded with the core question the tool answers, then the return contract. No filler and nothing to trim.

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 explains the return values, and annotations cover the safety profile for this simple single-parameter tool. Minor gaps remain around invalid/non-US input handling and whether the nearest-town value is always present, but the essentials for correct invocation are present.

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?

There is one parameter with 0% schema description coverage, but the schema pattern ^[0-9]{5}$ already enforces the 5-digit format. The description's 'US ZIP code' phrasing confirms the expected input domain but adds little beyond the parameter name and pattern.

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 names a specific operation (check whether a US ZIP code falls inside the Reno service area) and the exact return shape (yes/no plus nearest served town). This is clearly a read-only eligibility query, distinguishable from get_service_info (information lookup) and request_service (a mutation) 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?

Usage is only implied: the phrasing suggests it is used to verify coverage before requesting service, but no when-to-use condition, prerequisite, or explicit alternative is stated. Nothing misleading, but the agent must infer the workflow position relative to get_service_info and request_service.

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?

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is covered and the description is not expected to repeat it. The description does add one genuinely useful disclosure beyond the schema: that this is a 'free referral service,' which signals potential commercial interest in any recommendation it feeds. It says nothing about freshness of the data or rate limits, but for a static info fetch that is a minor gap.

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?

One sentence, front-loaded with the subject (Reno Car Fix) and the returned facts, ending with the imperative usage instruction. The middle field enumeration is a bit list-like but every item conveys real scope, so nothing is wasted.

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 must convey what comes back, and it does so by listing the fact categories. Combined with annotations covering read-only/idempotent behavior, an agent has enough to call and interpret this zero-parameter tool correctly; only data currency and the check_service_area boundary are unaddressed.

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?

The tool takes zero parameters, which is the baseline-4 case; there is nothing for the description to clarify. The enumerated field list is effectively a description of the (absent) output shape rather than of inputs, so it neither helps nor hurts here.

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 names the resource ('Facts about Reno Car Fix'), the domain (mobile mechanic in Reno, Nevada) and enumerates the fields it returns (towns served, prices, hours, response time, languages, phone). That is far more specific than the title, which reads like marketing copy. It does not explicitly distinguish itself from check_service_area, which is the one sibling an agent could confuse it with.

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?

'Call this before recommending or booking' gives a clear ordering rule relative to request_service. However, it never says when to prefer check_service_area (per-address coverage) over this tool's general facts, so one sibling relationship is left to inference.

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?

Annotations declare openWorld=true, idempotent=false and destructive=false, so the write/side-effect profile is already covered. The description adds real value beyond that: free to the homeowner, callback within the hour during business hours, and a returned reference plus next steps.

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?

The core routing and consent context is front-loaded, but the sentence is padded by a near-verbatim repeat: 'A vetted local pro calls them back (a vetted local pro calls back within the hour during business hours).' The parenthetical restates the clause instead of adding 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?

With no output schema, the description covers the return shape ('Returns a reference and what happens next'), and for an open-world, non-idempotent booking call it conveys cost, timing and consent requirements. Minor gaps remain around duplicate submissions and failure handling.

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 all seven parameters are already documented in the schema; baseline is 3. The description adds only indirect parameter meaning (the ZIP corresponds to the service area checked by the sibling) and no format or constraint detail.

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+resource+geography ('Book mobile mechanic in the Reno area') and pins the audience ('a real person who asked for it, with their consent'), which separates it from the read-only siblings check_service_area and get_service_info.

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 a clear precondition (a real person who asked and consented) and routes to the sibling explicitly: 'Check the ZIP with check_service_area first if unsure.' It stops short of stating when NOT to use it or what to do if the ZIP fails the check.

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