BART Real-Time Transit

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the tool's safe, read-only nature is known. The description adds the notion of 'current' data and the specific scope of advisories/status, but does not disclose additional behaviors such as response format, rate limits, or fallback when no advisories exist. It is consistent with annotations and adds minimal context beyond them.

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 description is a single, front-loaded sentence with a clear action verb ('Get') and explicit objects. There is no waste, and the structure immediately conveys the tool's purpose.

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?

Given the tool's simplicity (no parameters, output schema present, annotations provided), the description fully covers what the agent needs to invoke it correctly. It identifies the key content areas (advisories, delays, elevator/escalator status) and the timeliness ('current'), making it a complete and self-sufficient description.

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 has zero parameters, so the baseline score is 4. With an empty input schema and 100% schema coverage, the description does not need to explain parameter semantics. The lack of parameters is fully represented, and the description does not claim or imply any parameters.

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 clearly states the tool's action ('Get') and target (current BART service advisories, delays, and elevator/escalator status). However, it does not explicitly differentiate it from the sibling tool 'bart_status_summary', which likely overlaps in the general status domain, though the mention of elevator/escalator adds specificity.

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?

No guidance is provided on when to use this tool versus alternatives like 'bart_status_summary' or 'bart_departures'. There are no explicit use cases, exclusions, or prerequisites, leaving the agent to infer the appropriate context.

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 indicate readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the station abbreviation format and optional direction, but does not disclose additional behaviors like rate limits, data source, or output details. No contradiction with 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?

The description is exceptionally concise, with a clear purpose statement followed by a compact arg list. It is front-loaded and free of unnecessary prose. The arg list is slightly redundant with the schema, but this does not detract from overall clarity.

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 simple read-only tool with good annotations and output schema, the description is largely sufficient. It covers the core purpose and essential parameter syntax. However, it lacks context on direction semantics (e.g., which directions correspond to n/s) and when to prefer this over sibling tools, leaving minor gaps.

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% (both parameters have descriptions). The description's arg list mostly repeats schema information, adding '4-letter abbreviation' and 'Optional,' which are already implied by schema constraints (minLength, required, enum). Minimal added value beyond schema.

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 clearly states the tool's function with a specific verb and resource: 'Get real-time departures from a BART station.' This distinguishes it from sibling tools like bart_advisories, bart_fare, and bart_trip, which serve different purposes.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention exclusions, prerequisites, or appropriate scenarios, beyond implying the need for a station abbreviation.

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 and destructiveHint=false, so the safety profile is clear. The description adds no additional behavioral context, such as fare calculation assumptions or possible variations, providing minimal value beyond 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?

The description is a single, front-loaded sentence that directly states the tool's function. There is no unnecessary detail or repetition, making it highly concise and effective.

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 simple tool with complete schema coverage and rich annotations, the description is sufficient. It could optionally mention ticket types or fare classes, but the output schema likely covers return values, so the description remains adequate for its scope.

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 input schema fully documents both parameters with 100% coverage, so the baseline is 3. The description does not elaborate on station code formats or expected values, merely reinforcing what the schema already states.

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 clearly states the verb 'Get' and the resource 'fare' with the scope 'between two BART stations', which distinguishes it from sibling tools like bart_trip or bart_departures. It is specific and 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?

The description implies use for fare queries but provides no explicit guidance on when to choose this tool over alternatives such as bart_trip. There are no exclusions or prerequisites mentioned, so the usage context is only 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?

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds no extra behavioral details beyond the search criteria, such as matching semantics or pagination behavior. It does not contradict annotations, but it also doesn't enrich them.

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 description is a single concise sentence that front-loads the verb and resource, with no wasted words. Every phrase adds relevant information about the search scope.

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?

Given the tool's simplicity, the presence of an output schema, and complete parameter documentation, the description is adequate for an agent to invoke it correctly. It lacks only explicit guidance on when to prefer this over 'bart_stations', but that falls under usage guidelines rather than completeness.

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%, with each parameter already well-described. The description's mention of searching by name, city, etc., is largely redundant with the 'query' parameter description. It adds marginal value by grouping search dimensions but does not compensate for any schema gaps.

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 clearly states a specific verb ('Search') and resource ('BART stations'), and specifies the search dimensions (name, city, address, or 4-letter station code). It distinguishes itself from siblings like 'bart_stations' which likely lists all stations rather than searching.

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?

The description implies usage for finding a station via search criteria, but it does not explicitly contrast with alternatives like the 'bart_stations' sibling for listing all stations, nor does it state when not to use this tool. The intended use is inferable but not directly guided.

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 destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context by specifying the output content (abbreviation codes and locations) but does not go further (e.g., pagination, ordering). With strong annotation coverage, a 3 is appropriate.

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 description is two sentences and front-loaded with the main action ('List all BART stations'). The second sentence provides a clear use case without redundancy. Every word earns its place, making it highly concise.

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?

Given the tool's simplicity (no params), the presence of an output schema, and strong annotations, the description is complete. It tells the agent what the tool returns (stations with codes and locations) and why to use it (look up codes for other tools). There is no missing context for successful invocation.

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 has zero parameters, and the input schema is empty, so schema coverage is 100% by default. Per the rubric, 0 params earns a baseline of 4. The description adds meaning about the output rather than parameters, which is fine since there are no parameters to explain.

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 uses the specific verb "List" and clearly identifies the resource as "all BART stations" with included fields ("abbreviation codes and locations"). It also distinguishes the tool by its role in "look[ing] up station codes needed by other tools," separating it from sibling tools like bart_station_lookup.

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?

The description explicitly states when to use this tool: "Use this to look up station codes needed by other tools." This provides clear context. However, it does not mention any alternatives or when not to use it, so it doesn't fully meet the "explicit when/when-not/alternatives" bar.

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 and destructiveHint=false, covering the safety profile. The description adds that the tool draws from advisories and real-time alert data, which is useful context, but it does not disclose output format or other behavioral traits. Since the output schema exists, this is adequate.

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 description is a single, front-loaded sentence that communicates action ('Summarize'), resource ('BART service status'), and data source without any redundant words. It is concise and well-structured.

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?

Given the tool's simplicity (zero parameters, annotations provided, output schema present), the description is complete. It clearly explains what the tool does and where data comes from, and the structured information covers the rest, making it sufficient for an agent to select and invoke the tool correctly.

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 has zero parameters, so the baseline is 4. The description does not need to explain parameter details, and the absence of parameters is clearly indicated by the empty input schema.

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 uses a specific verb 'summarize' with a clear resource 'current BART service status' and identifies data sources ('advisories and real-time alert data'). This distinguishes it from sibling tools like bart_advisories, which likely provide raw alerts, by emphasizing the summary aspect.

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?

The description implies a clear context for use: when the user needs a summarized status overview. However, it does not explicitly mention alternatives or state when not to use this tool, such as directly referencing bart_advisories for detailed raw alerts. Still, the provided context is sufficient for most cases.

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 and destructiveHint=false, so the safety profile is covered. The description adds that it returns schedule, fares, and transfer info, but does not disclose other behavioral traits such as data freshness, timezone handling, or multiplicity of results. It does not contradict 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?

The description is two sentences: the first states the core purpose, the second summarizes the return value. It is front-loaded and every word earns its place with no redundancy or ambiguity.

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?

Given the output schema exists and annotations provide safety context, the description is adequate for a tool of moderate complexity. It covers the essential purpose and outputs, though it could note prerequisites (e.g., valid station codes) or clarify that it returns full trip plans with transfers. However, these are not critical gaps.

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 all parameters (origin, destination, date, time) with reasonable descriptions. The tool description adds no additional parameter semantics beyond reiterating that it is between two stations, which is already implied by the schema fields. 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?

The description uses a specific verb ('Plan') and resource ('trip between two BART stations') and clearly states what it returns ('schedule, fares, and transfer info'). It is clear but does not explicitly differentiate from sibling tools like bart_departures or bart_fare, though the combined output implies a distinct purpose.

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?

The description implies usage when planning a trip between two stations and lists the outputs, but it does not explicitly state when to choose this tool over alternatives (e.g., bart_departures for departures only, bart_fare for fares only). No exclusions or alternatives are mentioned.

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