Agents Get Paid Kit — x402 MCP + Unlock ($49)

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

With annotations absent, the description carries full burden for behavioral disclosure. It discloses that this is a free quote, implying no cost, and mentions it covers spend caps and allowed purposes. However, it does not disclose whether it returns live data, requires authentication, or has rate limits. It does not state if the quote is deterministic or may vary. Since annotations provide no safety or read-only hints, this is a significant gap.

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 concise and front-loaded with the key information (free quote, USD retail card). All terms are meaningful, and there is minimal fluff. However, the phrase 'plan agent USDC monetization before pay' is somewhat cryptic and could be clearer, costing a point from perfection.

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 tool with one optional parameter and no output schema, this description provides a reasonable starting point. It covers the return value's nature (free quote with spend caps and allowed purposes). However, it does not explain what the quote includes in terms of exchange rate or fee structure, and it lacks guidance on how the 'kind' parameter affects results. Given the tool's relatively low complexity, it is adequate but not 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%, fully describing the optional 'kind' parameter with valid examples. The description adds context by implying that 'kind' may affect the quote (e.g., captcha kind), but it does not explicitly explain the parameter's impact. Given the schema already covers syntax and options, the description adds modest value beyond it, but it's not a major 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 clearly states the tool provides a quote for spending limits and allowed purposes on a USD retail card, using specific terms like 'x402 list prices' and 'spend caps'. This distinguishes it from the siblings, which handle status, issues, captcha, and page unlocking. It could be slightly more explicit about being a read-only quote versus a live exchange rate, but the purpose is clear.

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 planning USDC monetization, giving a clear context. However, it does not explicitly state when to use this tool versus alternatives, nor does it mention any excluded scenarios. The phrase 'before pay' suggests using it before payment, but it lacks direct guidance on when not to use it or which sibling to prefer.

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 burden. It partially carries it by disclosing that the data is 'in-memory' (ephemeral, not persisted), that it operates on 'this isolate,' that it's an 'MVP' (minimal functionality), and 'Free' (no cost). The verb 'show' plus 'in-memory' reasonably implies a non-mutating read operation. However, it stops short of describing the response shape, what happens if no spend data exists, or the relationship between 'isolate' and the tenantId parameter — meaningful gaps given the absence of any annotation support.

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 short sentences with no filler: the core purpose is front-loaded, and the trailing 'Free' is one word. It is appropriately compact for a simple read tool. It loses a point because the parentheticals '(MVP)' and 'Free' are informal noise that could clutter a definition meant for machine-reading agents, and brevity here borders on under-specification rather than pure conciseness.

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 low complexity (one optional param, no enums, no nested objects, no required fields), the description is mostly adequate. But with no output schema and no annotations, the agent is left unaware of the return format, and the phrase 'this isolate' conflicts with the parameter tenantId — the description never clarifies whether an isolate is a tenant or a separate notion. For a minimal MVP this is borderline acceptable, but the response shape and scoping ambiguity are real gaps that a fuller description should resolve.

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%, and the single optional parameter tenantId already carries a complete description ('Optional tenant key; default ''default'''). The tool description adds no parameter-level meaning — it does not mention the parameter or how 'isolate' relates to a tenant. Per the baseline rule, with full schema coverage a 3 is appropriate since the schema does the heavy lifting and the description neither helps nor hurts.

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 states a clear action ('Show in-memory spend / rate usage') with a specific scope ('for this isolate'), using the verb 'show' plus a concrete resource. It is a specific, non-tautological statement that names the domain (spend/rate usage). It does not name a sibling to differentiate from, but the sibling set (get_quote, report_issue, solve_captcha, unlock_page) is clearly unrelated, so little ambiguity exists. Not a 5 because it doesn't explicitly contrast with any sibling.

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 no guidance on when to call this tool versus alternatives, nor any exclusions or prerequisites. There is no 'use this when...' or 'for X instead use Y' statement. The only implied context is 'when you need spend/rate status,' which is inferable from the purpose but never stated. With no direction on tenant scoping or when the read applies, this dimension is a clear gap.

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. It discloses two behavioral traits: the report is 'logged server-side' and it is 'Free.' This is useful, but it omits other important details such as whether a ticket or confirmation is returned, whether authentication is needed, and any side effects beyond logging. There is no contradiction, but the disclosure is thin.

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 tightly worded sentence with the action front-loaded. 'Free.' is short and delivers cost-relevant context without padding. Every word earns its place, and there is 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?

The tool has three parameters and no output schema, so the description needs to explain what to provide and what to expect in return. It only says the issue is logged, leaving the required summary field, the purpose of toolName, and the response behavior unexplained. This is inadequate for safe and correct 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?

Schema description coverage is 0%, so the description must compensate, but it mentions none of the three parameters. It does not explain that summary is required, what detail or toolName represent, or any length constraints. The description adds no value for parameter understanding.

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 'Report' with the resource 'product or policy issue', making the action unmistakable. The parenthetical 'logged server-side' adds scope, and the siblings (get_quote, get_spend_status, solve_captcha, unlock_page) are all clearly unrelated, so no confusion is possible.

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 when to use the tool: when there is a product or policy issue to report. However, it provides no explicit context, exclusions, or alternatives, and does not mention situations where a sibling tool would be more appropriate. The usage guidance is present only by implication.

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 empty annotations, the description carries the full behavioral burden and does disclose meaningful traits: the operation is paid in USDC, subject to spend caps, and will refuse disallowed uses. This goes beyond the schema and helps agents anticipate cost and refusal behavior. It does not cover failure modes or outputs, but the disclosed behavior is substantial.

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 payment, context, policy limits, and refusal behavior without filler. Every clause adds information relevant to invocation decisions. This 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?

This is a paid, policy-restricted tool with seven parameters and no output schema, so the description needs to cover operational details like which parameters apply per CAPTCHA kind and what the solve result looks like. The current description covers cost and policy but omits these invocation-critical details. It is not complete enough for an agent to confidently construct a correct request.

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 only 43%, so the description should compensate by explaining parameters or their relationships, but it does not. It mentions purpose restrictions but not how to populate kind, websiteURL, imageBase64, websiteKey, or tenantId, nor how these interact for different CAPTCHA types. The agent is left to infer parameter semantics from the sparse 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 'solve' with the resource 'CAPTCHA' and adds the context 'for agents mid-task,' making the core function clear. It is distinguishable from the sibling tools listed, which cover quoting, spend status, issue reporting, and page unlocking. It stops short of an explicit sibling comparison, but the function is 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 provides explicit usage context: it is for mid-task CAPTCHA solving, subject to spend caps and AUP, and restricted to allowlisted purposes. It names clear exclusions by refusing login, signup, and payment abuse. It does not name sibling alternatives or say when to use get_quote first, but the conditions for use are mostly explicit.

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 are empty, so the description carries the burden. It discloses that this is a paid operation with spend caps and an acceptable use policy, and mentions HTTP 402 payment-required. However, it does not reveal what the tool returns (content, status, error format), behavior on insufficient funds, or any rate limits. Partial 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 efficiently written in three short lines, with the core purpose front-loaded. No unnecessary fluff. Minor cryptic jargon like 'x402' and 'HTTP 402' slightly reduces accessibility, but overall it is appropriately sized and 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?

For a paid tool with no output schema, the description is incomplete. It does not explain what the response looks like, how to obtain a quote or check spend status (sibling tools exist but no pointers), or what happens when the AUP is violated. The absence of these details leaves an agent guessing about the full flow.

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 only 33% (only 'purpose' has a description). The tool description provides no information about parameters 'url' or 'tenantId' beyond the schema's basic type/format. Given the low coverage, the description should compensate but does not, leaving the agent without clarity on how to fill required fields semantically.

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 web pages (unlock) and involves payment in USDC via x402. It names the resource (pages) and the action (fetch/unlock). While it doesn't explicitly distinguish from siblings like get_quote, the core intent is unmistakable and distinct from the supporting tools.

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. It implies use for 'legitimate research/indexing' and mentions spend caps and AUP, but does not suggest calling get_quote first, checking spend status, or handling cases where payment is required. The agent is left to infer usage context.

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