x402 Web Extract

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

With no annotations, the description carries the full burden. It discloses the 0.01 USDC cost on Base, a key behavioral trait, and notes it works on public URLs, implying no auth needed. It does not detail error handling or limits, but the essential behaviors are 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 two sentences, front-loaded with purpose and output, followed by the parameter guidance and cost. Every word earns its place—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?

For a one-parameter fetch tool, the description covers purpose, parameter format, cost, and output type. It does not mention limitations like content size or redirect behavior, but the tool's simplicity and the absence of an output schema make this adequately 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?

The schema provides no parameter description, so the description compensates by explicitly saying 'Pass the target as url (http/https)', which gives the format and valid scheme for the url parameter. It adds meaning beyond the raw schema, though it does not elaborate on encoding or validation.

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 fetches any public URL and returns a clean, readable markdown or JSON extract. The verb 'Fetch' plus the resource 'URL' is specific, and it distinguishes itself from the sibling crypto/YouTube tools by its general web-fetching 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?

It provides clear context: the tool fetches any public URL and the url parameter must be an http/https target. It does not explicitly mention when not to use it or name alternatives, but the sibling tools are unrelated domains, so the use case is well 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?

No annotations are provided, so the description carries the full transparency burden. It discloses the cost ('Costs 0.01 USDC on Base'), the real-time nature, and the default chain. However, it doesn't mention error behavior, rate limits, or what happens for invalid addresses/symbols, keeping it at a moderate level.

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 with no filler. The first sentence states the purpose, and the second covers inputs, chain options, default, and cost—every word 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?

The description covers purpose, input methods, chain list, default, and cost. It implies the return value is a USDC-denominated spot price, which is sufficient given the lack of an output schema. It could mention edge cases or restrictions, but overall it's adequately complete for a simple price lookup.

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?

With 0% schema description coverage, the description compensates by explaining all three parameters: address (0x...), symbol (with specific examples), and chain (with a list and default). It implies address and symbol are alternatives via 'or,' but doesn't explicitly state mutual exclusivity, which is a minor gap.

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 opens with a clear verb ('provide') and identifies the resource: 'real-time USDC-denominated spot price for an EVM token by contract address or common symbol.' It easily distinguishes from sibling tools like fetch_url or wallet_balance, which are unrelated.

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 instructs how to use the tool: 'Provide address (0x...) or symbol (ETH, USDC, USDT, WETH) and optional chain (base, ethereum, polygon, arbitrum, optimism, avalanche, default base).' It implies when to use it (whenever a token price is needed) and lists chain options, though it doesn't name alternative tools since siblings are clearly unrelated.

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 carries the full burden and does disclose the cost (0.02 USDC on Base) and the scope of results (native and USDC). It omits error behavior or authentication requirements, but the cost disclosure adds value beyond the schema.

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 the primary action, and each sentence serves a purpose: address format, chain options, default, and cost. No redundant wording.

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 no output schema, the description covers input parameters, return type (native and USDC balances), and cost. It is slightly ambiguous whether the cost applies only on Base or all chains, but overall it's adequate.

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 0% description coverage, so the description fully compensates by specifying the address format (0x...), enumerating chain values (base, ethereum, polygon, arbitrum, optimism), and stating the default (base). This is essential meaning absent from 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's function with a specific verb ('Query') and resource ('native and USDC balance for any EVM wallet address'). It distinguishes from sibling tools like fetch_url or token_price by focusing on wallet balance.

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 clear usage context: it's for querying balances of EVM addresses, with an optional chain parameter and default base. However, it does not explicitly mention alternatives or exclusions, so it lacks when-not-to-use guidance.

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 burden. It transparently discloses the cost (0.50 USDC on Base) and notes format availability ('m4a/webm when available'), which is valuable. However, it does not mention potential errors, rate limits, or authentication, so it falls short of a 5.

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 only two sentences, front-loading the core action and adding the cost in the second sentence. Every word earns its place, with no redundant or irrelevant 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?

This is a simple one-parameter tool with no output schema, and the description provides essential context: the resolved output type, metadata returned (title, uploader, format), and cost. It is complete enough 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?

Schema description coverage is 0%, so the description must compensate. It does so by specifying 'Provide url (http/https)', which adds a clear format constraint beyond the bare schema type 'string'. The phrase 'any YouTube video URL' also clarifies acceptable 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 the tool resolves a YouTube video URL to an audio-only stream download URL, with a specific verb and resource. It also distinguishes itself from the sibling youtube_video tool by specifying the audio-only output and metadata field.

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 audio downloads by emphasizing 'audio-only stream download URL' but does not explicitly mention when to use this tool instead of alternatives like youtube_video. There is no exclusion criteria or comparison to sibling 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?

No annotations are provided, so the description must disclose behaviors. It adds cost information ('Costs 1.00 USDC on Base') and input format requirement ('Provide url (http/https)'). However, it does not disclose authentication needs, error behavior, or whether the MP4 link is temporary, leaving some gaps.

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 compact, front-loaded with the main purpose, and each sentence adds useful information (purpose, input format, cost). 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?

The tool is simple with one parameter and no output schema or annotations. The description conveys input, output fields, and cost, but lacks details on response structure and potential errors, making it adequate but not fully 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?

The schema provides only a bare string parameter with no description. The description compensates by listing accepted URL formats (watch?v=, youtu.be, shorts, embed) and requiring http/https, adding practical meaning 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 uses the specific verb 'Resolve' and clearly states the tool converts YouTube video URLs to MP4 download URLs with metadata. It also lists accepted URL formats, distinguishing it from the sibling youtube_audio by specifying MP4.

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 clearly indicates this tool is for YouTube video URLs and returns MP4, implying use for video rather than audio. However, it does not explicitly name alternatives or exclusions, so it earns a 4 rather than a 5.

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