PRD to Flutter APK

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

With no annotations provided, the description must disclose behavioral traits, but it only lists content types without stating whether the tool is read-only, requires authentication, or has side effects. The read-only nature is implied by the name and context but never explicitly stated, nor are any other behavioral aspects covered.

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 sentence that lists key items, making it concise and efficient with no wasted words. It could be slightly improved by adding a verb like 'retrieves' to make it more action-oriented, but it is still well-structured and front-loaded.

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 has only one parameter and no output schema, the description provides a basic list of what is returned but lacks details on response structure, possible status values, or any caveats. It is adequate for a simple tool but leaves gaps in what the user might expect from the output.

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 schema has a single parameter (job_id) with no description, and the tool description does not mention it at all. Schema coverage is 0%, and the description does not compensate by explaining what job_id represents or how to obtain it, leaving the user to infer it is the build identifier.

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 identifies the tool as providing status, log, diagnostics, settlement transaction, and token usage for a build. It focuses on a specific resource ('a build already paid for') and is distinct from siblings like start_build and validate_prd, which relate to initiating or validating rather than checking post-payment details.

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 'already paid for' implies the tool should be used after payment to check a build's details, but there is no explicit statement of when to use it versus alternatives. No exclusions or alternative tool references are given, so usage is only implied.

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 must disclose behavioral traits. It mentions 'Free' and the x402 challenge but does not clarify whether the tool is read-only, has side effects, or requires any authentication. The meaning of 'Free' is ambiguous—could imply zero cost for the build or that the tool itself is free to invoke.

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 extremely short (about 15 words) and front-loaded with purpose. The trailing 'Free.' is an extra fragment that adds slight confusion but overall the description is economical and to the point.

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?

The tool is simple (0 params, no output schema), so the description carries the burden of explaining return values. It lists the key fields (price, token contract, chain, EIP-712 domain) but does not clarify the response format or the meaning of 'x402 challenge' and 'Free'. This leaves some ambiguity for an agent unfamiliar with the domain.

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 adds value by explaining what the output will contain (price, token contract, chain, domain), which is helpful given no output schema. No parameter documentation is needed because none exist.

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 identifies the tool as providing payment-related information (cost, price, token contract, chain, EIP-712 domain) for a build. It distinguishes from sibling tools like build_status or validate_prd. However, it lacks an explicit verb like 'returns' or 'gets', making it slightly less direct.

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 explicit guidance on when to use this tool versus alternatives. The description does not mention any prerequisites, context, or exclusions. Sibling tools exist but are not referenced, leaving the agent to infer usage from the name and content.

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 are provided, so the description must carry the burden. It implies the tool outputs a schema to reference, but it doesn't explicitly state the return format, that it's read-only, or any limitations. The guidance adds some behavioral context but lacks full transparency.

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 concise, front-loaded sentences. The first defines the schema, the second gives practical usage advice. Every word earns its place with no 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 simple tool with no parameters and no output schema, the description covers the essential context: what the tool is and how to use it. It doesn't mention the relationship to validate_prd, but that's not strictly necessary for basic usage.

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 an empty input schema, so the baseline score of 4 applies. The description doesn't need to explain parameters, and it doesn't attempt to.

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 explicitly states the tool provides the JSON Schema that product requirements documents must satisfy, and advises generating against it. This clearly identifies the resource (schema) and its purpose, distinguishing it from sibling tools like validate_prd or start_build.

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 instruction 'Generate against this rather than guessing field names' gives clear context for when to use the tool: when creating a PRD. It doesn't explicitly name alternatives or exclusions, but the intended usage is unambiguous.

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 provided, the description carries the full behavioral burden and succeeds. It discloses that payment settles on-chain before the build starts, that a failed build returns diagnostics, the approximate build duration (5-8 minutes), and the expected return shape (job id, apk_available, apk_url).

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 four purposeful sentences, front-loaded with the core action ('Buy a build'). Each sentence delivers necessary information—protocol, return value, timing, and payment behavior—without unnecessary detail or repetition.

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?

Even without an output schema, the description covers the full lifecycle: how to initiate, what to expect (job id), how to track (poll with build_status), and how to retrieve the APK. It also references prd_schema for the nested object structure and explains payment/failure behavior, making it complete for the tool's complexity.

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 covers parameter descriptions at 100%, but the description adds critical process context: it explains the two-call flow where x_payment is the signed authorization obtained from the first call, and that omitting it triggers a quote. This goes beyond schema by clarifying parameter interplay.

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 explicitly states the tool's function with a specific verb ('Buy a build') and resource, and articulates a clear two-step payment workflow. It indirectly distinguishes itself from siblings by referencing build_status for polling and prd_schema for PRD structure, making its 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 explicit step-by-step usage instructions: call without x_payment to get payment requirements, then call again with signed authorization. It directs the agent to poll using build_status and consult prd_schema, effectively demonstrating when to use this tool versus alternatives.

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 are provided, so the description carries the burden. It discloses non-destructive behavior ('without building it'), zero cost, and consistency with the paid validator. It lacks detail on side effects like data retention, but for a read-only validation tool this is sufficient.

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 sentences, front-loaded with the main action, and includes only essential information (free, same validator). There is no redundancy or fluff.

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 one parameter and no output schema, the description covers purpose, cost, and validation consistency. It does not specify the output format or failure behavior, but for a simple validation tool, this is reasonably 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 coverage is 100% with a single parameter 'prd' described as 'the PRD; see the prd_schema tool.' The description adds domain context (screens, models, navigation, auth) but no format or syntax details, so 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 clearly states the tool checks a PRD and reports exactly what would be built (screens, models, navigation, auth) without building it. This distinguishes it from siblings like start_build, making the purpose 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 says 'Free, no payment required' and 'anything accepted here will not be rejected after payment,' implying use before paying to validate a PRD. It contrasts with start_build by saying 'without building it,' but does not explicitly name alternatives or when-not-to-use scenarios.

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