Opus 4.8 Agent

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

Description adds value beyond annotations by clarifying no model execution and no token requirement. No contradictions 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?

Two sentences, front-loaded with return values, no unnecessary words.

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?

All relevant information provided: return fields, non-execution nature, authentication requirement. Adequate for a zero-parameter metadata 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?

No parameters, baseline score 4. Description doesn't need to elaborate on parameter meaning.

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?

Description uses specific verb 'Returns' and lists concrete resources (identity, per-task price, MCP endpoint, access URL). Clearly distinguishes from sibling tools which are about run creation and status.

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 states 'does not run the model' and 'does not require a bearer token', guiding when to call it. Could be improved by mentioning alternatives, but given context it's clear.

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 destructiveHint=true and idempotentHint=true, and the description's 'Cancels' aligns with these. The description adds the 'queued or running' state restriction and implies an auth context, but it does not disclose what happens after cancellation (e.g., whether results become unavailable or if it can be resumed). 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?

A single, front-loaded sentence with zero filler. Every word contributes: the action, the target resource, and the state constraint. This is appropriately 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?

For a simple one-parameter cancellation tool with annotations covering destructiveness and idempotency, the description is sufficiently complete. It lacks detail about error responses or behavior for invalid run states, but no output schema exists and the operation is straightforward.

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%; the single parameter run_id is already documented as an 'AgentFarm run identifier.' The description adds no further parameter details, so the schema carries the semantic burden. Baseline 3 is appropriate.

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 'cancels' with the resource 'run' and a clear state qualifier ('authenticated queued or running'). This unambiguously distinguishes the tool from its siblings (create_run, get_run_status, get_run_result, agent_info) which perform different operations.

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 phrase 'queued or running' provides clear context about which run states are eligible for cancellation, implicitly telling the agent not to use this tool on completed or failed runs. It gives useful conditions, though it does not explicitly name alternatives or exclusions.

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?

The description adds valuable behavioral context beyond the annotations: the task is asynchronous, requires authentication, and 'can consume paid model capacity.' This is important cost and execution semantics that an agent needs before invoking the tool. Nothing contradicts the annotations, and the description meaningfully supplements the all-false hint set.

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 three short sentences with no filler. It front-loads the core action, then adds the cost warning and the follow-up workflow. Every sentence earns its place.

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 an asynchronous create-type tool with no output schema, the description provides enough context to invoke it and proceed correctly: it is async, costs money, and the result is obtained through explicit sibling tools. A small gap is that it does not describe what create_run returns, such as a run ID needed for polling, but the workflow implication is strong enough to keep this near-complete.

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 task, task_input, and idempotency_key. The description does not add additional parameter-level meaning, but it also does not need to because the schema carries that load. Baseline 3 is appropriate.

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 and resource: 'Queues an authenticated asynchronous task.' This clearly identifies the action as creating/queueing a run and distinguishes it from the sibling tools that retrieve status, retrieve results, cancel, or return agent info. The follow-up references to get_run_status and get_run_result further reinforce what create_run is not.

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 gives clear workflow context: after creating a run, the agent should poll with agentfarm_get_run_status and then read the result with agentfarm_get_run_result. This effectively tells the agent when this tool fits in the overall lifecycle. It does not explicitly state exclusions or when to prefer alternatives like agentfarm_cancel_run, but the intended usage is clear.

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 and idempotentHint, covering safety and repeatability. The description adds the return content (summary and URLs) but no extra behavioral context beyond what annotations provide.

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?

Single sentence, front-loaded with the action and key output. No wasted words.

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 one parameter and no output schema, the description adequately covers the return value (summary and download URLs). Complexity is low, so completeness is sufficient.

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% for the single parameter run_id. The description does not add additional meaning or constraints beyond the 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 returns the final summary and artifact download URLs for a run, using a specific verb and resource. It distinguishes from siblings like agentfarm_get_run_status (status) and agentfarm_create_run (creation).

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 on when to use this tool versus siblings (e.g., get_run_status). It only implies authentication is needed but doesn't specify prerequisites or alternative tools.

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, destructiveHint=false, so the safety profile is clear. Description adds the possible status values (queued, running, succeeded, failed), which is useful but not extensive.

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?

Single sentence, no redundant words or information. Perfectly 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?

For a one-parameter read-only status tool with good annotations, the description is largely adequate. Could optionally mention that exactly those four status values are returned, but not required.

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% and describes run_id as 'AgentFarm run identifier.' The description does not add any additional semantics beyond the 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?

Description states a specific verb ('returns') and resource ('status for an authenticated run') and clearly differentiates from siblings (agent_info, create_run, get_run_result) by focusing on status.

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 on when to use this tool versus siblings (e.g., before calling get_run_result). The phrase 'for an authenticated run' provides minimal context but no explicit when/when-not advice.

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