x402image

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

Discloses cost ($0.005 per call) and output nature ('short-lived signed URL'), adding value beyond annotations (readOnlyHint=false, openWorldHint=true). Does not mention rate limits or side effects but sufficient for context.

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?

Four concise sentences with zero waste, front-loaded purpose, efficient parameter description.

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 input, parameters, output (signed URL), and cost. No output schema, but description explains return value adequately. Could note error handling or expiry but acceptable for low complexity 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?

Adds default value for quality (85) and confirms requirement of at least one parameter, supplementing the schema which already has enums and range but lacks defaults and dependency hints.

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 verbs ('Convert format and/or compress') and identifies the resource ('image'), clearly distinguishing from siblings like 'resize' or 'remove_background'.

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 clear parameter constraints ('At least one of format/quality is required') and input type (source URL), but lacks explicit when-not-to-use or sibling comparisons.

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?

Discloses payment requirement, pricing model, error response (402 quote), and output format (short-lived signed URL), adding significant value beyond minimal 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?

Concise yet comprehensive; every sentence adds unique value. Front-loaded with purpose and cost, then input format, then references to service_info, then output.

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 no output schema, description adequately explains output and error handling. References sibling tools for further info, making it self-contained for its 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 already covers 100% of parameters; description adds concrete example and structure for 'steps' array, enhancing understanding beyond schema definitions.

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?

Clearly states the tool applies an ordered pipeline of image ops in a single paid call, distinguishing it from sibling atomic tools like resize or remove_background.

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 clear context for use (combining multiple ops in one payment) and references service_info for available ops and pricing. Missing explicit when-not-to-use, but 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?

Discloses cost, mutative nature (removes background), output expiration (short-lived signed URL). Adds value beyond annotations (readOnlyHint=false, openWorldHint=true) by explaining output behavior and transparency with PNG/WebP.

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 sentences, front-loaded with purpose, no redundant information. Every sentence adds value.

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 all aspects: input, parameters, cost, output format and lifespan. No output schema, but description explains return value adequately.

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?

Adds meaning beyond schema: explains source as public HTTPS URL, describes background parameter with examples and behavior (omit for transparent). Compensates for 50% schema description coverage.

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?

Clearly states 'Remove an image's background, isolating the subject' with specific model reference (BiRefNet). Distinguishes from sibling tools like resize and upscale.

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 usage context: $0.02 per call, input via source URL, optional background fill, output as short-lived URL. Does not explicitly exclude alternatives but context implies when to use.

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 indicate modification (readOnlyHint=false). Description adds cost per call and output format. Does not disclose side effects, limits, or error behavior. Adequate but not rich.

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?

Concise with three sentences covering purpose, cost, parameters, and output. Front-loaded. Could be more structured but 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?

Covers basic parameters and output, but lacks details on error handling, aspect ratio behavior when only one dimension given, and limitations. Adequate for a resize tool but leaves 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?

Description provides detailed parameter meanings for width, height, fit, gravity, and background, which are missing from schema (50% coverage). Adds value beyond schema by explaining behaviors like gravity focal point and background fill.

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?

Clearly states the tool resizes or crops images to exact dimensions. Specifies input via source URL and output as a short-lived signed URL. Distinct from sibling tools like 'optimize' or 'remove_background'.

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?

Implies usage for resizing/cropping images but lacks explicit when-to-use or alternatives compared to siblings. No do-not-use guidance. Context is clear but not definitive.

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 discloses it is free, requires no payment or input, which aligns with the readOnlyHint annotation. It adds value beyond annotations by stating the nature of the response (metadata and pricing). No contradiction.

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: first immediately states 'Free,' then the purpose and usage guidance. Every word earns its place; 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?

Despite no output schema, the description explains what will be returned (service metadata and list of paid tools with prices). This is sufficient for an informational tool with no parameters.

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 are zero parameters, and the description explicitly says 'no payment or input required,' which clarifies the empty schema. The baseline of 4 is appropriate because the description confirms there is nothing to input.

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 it returns 'x402image service metadata and the list of paid image tools with their per-call USD prices.' This distinguishes it from sibling tools which are specific image processing actions (optimize, process, etc.).

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 provides explicit guidance: 'Call this first to discover capabilities and pricing.' It implies this is the prerequisite step before using other 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 indicate readOnlyHint=false and openWorldHint=true. The description clarifies that the tool produces a 'short-lived signed URL' output, mentions pricing, and describes the AI process (ESRGAN). 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 three sentences, front-loaded with the primary purpose. Every sentence adds distinct value: purpose, pricing/input/params, and output. 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?

Given the tool's simplicity (2 params, no output schema), the description covers input, parameter constraints, output format, and pricing. It lacks details on supported image formats, size limits, or error scenarios, but is largely sufficient for a typical use case.

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 50% description coverage (only source has a description). The description adds semantics by clarifying that 'width and/or height' are target pixels and 'at least one required', which is not enforced in the schema. This provides valuable guidance 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 'Upscale an image with AI super-resolution (ESRGAN) for sharper enlargement.' It uses a specific verb (upscale) and resource (image), and distinguishes from siblings like 'resize' by mentioning AI super-resolution.

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 specifies input requirements (source URL) and parameter constraints (at least one of width/height), but does not explicitly state when to use this tool vs alternatives like 'resize' or 'optimize'. No exclusions or usage context is provided.

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