Sphere Marketplace

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

No annotations are present, so the description carries the full burden. It reveals that this is a paid service ('price 3 USDC', 'Sold by Sphere'), which is useful, but it does not disclose that this appears to be a marketplace purchase requiring registration, payment keys, or asynchronous result retrieval. The phrase 'Send a document' misleadingly suggests direct execution rather than a marketplace transaction.

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 and front-loads the key facts: what the tool buys, the price, and the basic input. It has no filler, though some of the brevity sacrifices necessary operational detail.

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 having 5 parameters, nested objects, no output schema, and no annotations, the description explains almost none of the workflow: how to pass api_key vs x_payment, what the document payload should look like, whether delivery is synchronous, or how to retrieve results. An agent would need external marketplace context to call this 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 coverage is 100%, so the baseline is 3; each parameter already has a description. The description adds only a high-level notion of document + optional question, which loosely maps to task_payload, but it adds little concrete value 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 names a specific verb ('Buy') and resource ('analyze_document'), and clarifies what the service does: send a document (text or file) and optionally a question. This is clear enough to distinguish from sibling tools like buy_analyze_image or buy_transcribe_voice, though it does not explicitly name alternatives.

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?

There is no guidance on when to use this tool versus related tools such as buy_summarize_text or buy_verify_claims_smart. The description implies usage by describing the document-analysis capability, but it gives no conditions, exclusions, or 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?

With no annotations, the description carries the full burden of explaining behavior. It discloses the price and the seller, but it does not explain how payment works, whether api_key, x_payment, or a marketplace contract is needed, what happens after submission, or how results are returned.

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 very short, front-loaded with the price and primary input, and has no real structural waste. 'Sold by Sphere' is minor filler, but overall the format is clear and scannable.

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 marketplace purchase tool with five parameters, no output schema, and no annotations, yet the description omits essential process details such as how to pay, whether a contract is created, deadlines, and how the analysis result is retrieved. The price and image-input mention are helpful but insufficient for confident 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 coverage is 100%, so the five parameters are already documented in the input schema; the description adds little beyond naming image and optional-question inputs. It maps loosely to task_payload but does not clarify the full payload contract, especially given the schema's own audio_file_path example.

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 a paid image-analysis service ('Buy analyze_image, price 1 USDC') and what the caller supplies ('Send an image and optionally a question'). It is distinct from sibling tools by its image focus, though it never states what analysis output the buyer receives.

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 'Send an image and optionally a question' implies the intended use case, but the description gives no explicit guidance on when to choose this tool over buy_analyze_document, buy_summarize_text, or buy_transcribe_voice. There are no exclusions, prerequisites, or alternative-selection cues.

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 exist, so the description carries the burden. It discloses the cost (2 USDC), the seller, and the deliverable, but doesn't describe payment mechanics, contract creation, or what happens on success or failure.

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?

One compact sentence with the key facts front-loaded: price, purpose, and what the user can send. 'Sold by Sphere' is slightly extra but not damaging.

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?

No output schema and no description of the return value or post-purchase behavior, so an agent cannot know what a successful call yields. For a paid marketplace tool with optional auth paths, this is a meaningful gap.

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 all 5 parameters with descriptions, so baseline is 3. The description adds high-level domain context (question, documents) but doesn't map to specific parameters beyond what the schema already provides.

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 names the exact resource (consult_bagira), states the action (buy), and clarifies the service as 'send a question about Sphere or its public knowledge, optionally with documents.' It goes beyond the name, though it still doesn't explicitly separate it from the other buy_* siblings.

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 about when to prefer this over other buy_* services or contact_sphere. Usage is only implied by 'question about Sphere', with no exclusions or 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 full behavioral burden. It discloses price and seller but does not explain what happens when the tool is invoked: whether it creates a contract, executes immediately, requires registration, or how the resulting xlsx is delivered. For a marketplace tool, this is a significant transparency 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?

Three short sentences with zero filler. The action and price are front-loaded, followed by the key deliverable. 'Sold by Sphere' is compact but conveys provenance. Every sentence earns its place; the structure aids quick parsing.

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 no annotations and no output schema, the description is too thin to fully guide an agent. It doesn't explain the purchase lifecycle, how results are retrieved, or how this relates to the sibling marketplace_* tools (e.g., marketplace_accept_contract, marketplace_get_result). The service context and expected follow-up steps are missing, making the description incomplete for a 5-parameter marketplace operation.

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 parameters are already documented to a baseline level. The description adds value by clarifying that task_payload should contain 'headers and rows with typed cells,' which maps to the actual service input better than the generic schema examples. This slightly exceeds the baseline but doesn't deeply elaborate on parameter formats.

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 names the specific resource (create_xlsx) and states its function: 'Send headers and rows with typed cells.' It is distinguishable from sibling buy_* tools by the service name and emitted artifact. However, 'Buy' as the leading verb focuses on the purchase action rather than the underlying spreadsheet-creation service, so the purpose is clear but slightly indirect.

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?

There is no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites, the marketplace contract flow, or how this buy path compares to marketplace_create_contract, x_payment, or other buy_* siblings. The intended usage must be inferred entirely from the tool name and bare description.

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 present, so the description carries the full burden of behavioral disclosure. It mentions a price and seller but does not explain how payment is charged, whether a contract or receipt is created, what the response will be, or what side effects the purchase has. 'Buy' implies a financial transaction, but the mechanics are absent.

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 short, but the 'what you get: Send...' construction is confusing and grammatically awkward. It front-loads the price but then packs unrelated details into a single run-on sentence, making it harder to parse than necessary.

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 5-parameter, no-output-schema, no-annotation purchase tool in a large marketplace sibling set, this description is severely incomplete. It omits what a sphere_receipt is, what the tool returns, how payment works, and how this differs from other buy_* tools. An agent cannot reliably decide to use it or invoke it correctly based on this description alone.

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 baseline is 3. The description adds a hint that task_payload should contain an agent's result, claims, and source text, which is useful but vaguely worded and not explicitly tied to any parameter. It does not clarify api_key, x_payment, or deadline_hours beyond what the schema already states.

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 'Buy sphere_receipt,' which essentially restates the tool name rather than defining its function. It adds price and seller but never clarifies what a sphere_receipt is or what action the tool performs, and the phrase 'what you get: Send an agent's result...' confuses inputs with outputs. It also does not distinguish this tool from siblings like buy_verify_claims_smart.

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 is provided on when to use this tool versus the many buy_* sibling tools. There is no mention of prerequisites, context, or alternatives, leaving the agent to infer usage from the minimal description. 'Sold by Sphere' identifies the seller but not the appropriate use case.

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 behavioral traits. It mentions price and that it's a purchase, but does not explain how the result is delivered (e.g., synchronous vs. contract-based), what happens after payment, or whether prerequisites like registration or api_key are needed. The description leaves the agent uninformed about the transaction flow.

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 (one sentence) and front-loaded with the price and what the user gets. There is no fluff, but it is perhaps too terse, omitting crucial usage details. Still, for conciseness, it is efficient.

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 no output schema and no annotations, the description must cover what the tool returns and how to use it. It does not mention the expected output (e.g., a summary in the target language) or how to provide the text/document within task_payload. It also doesn't explain the payment options (api_key vs x_payment) or any contract flow, making it incomplete for a purchase 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?

Schema coverage is 100%, so each parameter has a generic description. The tool description adds the key detail that task_payload should contain text/document and a target language, which is not explicit in the schema's generic example. However, it doesn't specify the exact structure of task_payload for this service, so the added value is partial.

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 a specific action ('Buy') and a resource ('summarize_text'), and it mentions the core inputs (text/document and target language). It distinguishes from sibling buy_* tools by the service name, though it doesn't elaborate on what the summarization does exactly (e.g., output language vs. translation).

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 summarization tasks but does not explicitly say when to use this tool over siblings like buy_analyze_document or buy_analyze_image. It lacks exclusion criteria or alternative guidance, though the service name itself provides clear intent.

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 but only reveals price, seller, and input. It does not disclose payment flow, authentication requirements, whether a contract is created, what response is returned, or any side effects beyond purchasing.

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 short and gets the core facts across quickly: buy action, price, input, and seller. However, it is a fragment rather than a clear sentence and omits operational details, so it is concise more than 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?

Given no output schema, no annotations, and five optional parameters, the agent is left without enough context to invoke the tool correctly. It does not explain authentication choices, payment method, expected return value, or how this purchase connects to the marketplace workflow.

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%, so the baseline applies. The description adds a hint that the service consumes an audio file, which loosely maps to task_payload, but it does not clarify the relationship between api_key, agent_id, and x_payment or how to structure the payload.

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 action as buying the 'transcribe_voice' service, names the price, and indicates the input is an audio file. This distinguishes it from sibling buy_* tools by service name, though it never explicitly states the service performs transcription.

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 is given on when to use this tool versus alternatives such as marketplace_create_contract, marketplace_x402_payment, or other buy_* tools. It also does not explain prerequisites like whether registration is needed or whether x_payment can be used instead.

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 of behavioral disclosure. It mentions the price (0.25 USDC) and vendor (Sphere), which is some useful context, but it does not explain the purchase flow, what happens after payment, whether it's a contract or immediate, or any other behavioral traits (e.g., rate limits, auth requirements).

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 concise sentence that front-loads the price and vendor, and then gives a brief functional hint. It has no wasted words and is easy to scan, though it could be more structured to separate the 'what you get' from the invocation details.

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 no output schema, no annotations, and a complex marketplace ecosystem, this description is insufficient. It does not explain what the service returns, how to structure the task_payload, or when to choose this over other buy_* tools. An agent would likely need additional context to use it 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 100%, so all parameters are already documented in the schema. The description adds only a vague hint about sending a result and claims (likely related to task_payload) but does not provide specific guidance on parameter values or structure. Baseline 3 is appropriate since the schema covers the semantics.

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 the verb 'Buy' and the resource 'verify_claims_smart', and hints at the input ('Send a result and the claims made about it'), but it does not clarify what the service actually does (e.g., whether it verifies claims) or how it differs from sibling buy_* tools. It is clearer than a tautology but still somewhat vague about the tool's function.

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?

There is no guidance on when to use this tool versus the many sibling buy_* tools or marketplace tools. No context is given for selecting it, no alternatives are mentioned, and no preconditions (e.g., requiring registration) are stated.

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 full burden. It discloses session continuity and that it returns a reply and session_id, but does not mention any side effects (e.g., creating records, sending emails), rate limits, or auth expectations beyond 'no key and no registration.' For a tool that might trigger collaborations or delegate work, this is a 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?

Two concise sentences that front-load the primary purpose and key value proposition (free, no key). The session continuation detail is placed logically. No redundant filler.

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 chat tool, the description covers the basics, but it omits guidance on the reputation-gated requested_action values and how the tool relates to contact_sphere_structured. The lack of an output schema means the description should describe the reply format more explicitly, but it does mention session_id and reply.

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 covers 100% of parameters, so the description adds minimal extra meaning. It clarifies session_id's role ('continue the same conversation across calls') and the no-key aspect, but does not explain the requested_action enum or agent_id behavior beyond what the schema already states.

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 purpose: 'Ask Sphere anything, propose a collaboration or reach a human.' It identifies a specific resource (Sphere/Bagira) and the action (asking, proposing, reaching). It doesn't explicitly contrast with the sibling contact_sphere_structured, but the free, no-key positioning helps distinguish it from the marketplace-related siblings.

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 general inquiries and human contact, and mentions continuing conversations via session_id. It does not explicitly state when not to use this tool or point to alternatives like contact_sphere_structured, leaving some inference to the agent.

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 of disclosing behavior, but it only states that the tool is free and requires no key or registration. It does not explain side effects, what happens when contact is made, or how marketplace-related parameters like api_key and agent_id fit in. The claim of 'no key' also creates ambiguity against the schema's api_key field.

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 brief and front-loaded, stating the relationship to contact_sphere and the target audience in the first sentence. The second sentence about being free adds some value, though it points to a possible contradiction with the schema.

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 five optional parameters, no output schema, and no annotations, the description is too thin. It does not explain the query actions, the role of api_key and agent_id, the meaning of requested_action values, or what a successful contact looks like. The dependency on 'same as contact_sphere' leaves too much unresolved.

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 all five parameters already have descriptive text. The description adds no meaning beyond saying the tool is 'structured and typed,' which is already reflected in the schema's enum values and structured_payload description.

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 identifies this as a structured, typed variant of contact_sphere for non-linguistic clients, which distinguishes it from the sibling tool. However, it never states what contact_sphere itself does, so the actual purpose depends on an undefined reference. The verb and resource are only implied, not explicitly described.

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 the intended use case: non-linguistic clients such as ROS2 robots via ros2_mcp. This implies when contact_sphere might be less appropriate, though it does not explicitly mention alternative tools or draw a hard exclusion boundary.

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 discloses that the tool is free, requires no API key, and is demo-only (not a Sphere product). These are meaningful behavioral traits beyond the schema. It does not mention error handling or output format, but for a simple demo tool, the essential behavioral aspects 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 exceptionally concise, comprising two sentences. It front-loads the critical caveat ('Demo only, not a Sphere product') and efficiently conveys the tool's purpose, cost, and alternatives. Every word serves a purpose, and there is no filler.

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 demo tool with one parameter and no output schema, the description provides enough context to call it correctly: it states the input (city), the behavior (free, no key), and its scope (demo only). It also directs the agent to the proper marketplace flow. While it doesn't describe the output format, that is less critical for a demo tool and not required given the absence of an output schema. Overall, it is adequately complete for its simplicity.

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 for the single 'city' parameter, and the description only says 'returns weather for a city' without adding details about what constitutes a valid city string (e.g., format, country, or examples). It essentially restates the parameter name without enriching it. For a tool with a single parameter, this is insufficient to guide the agent on how to populate it correctly.

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 verb ('returns weather') and the resource ('for a city'), and it distinguishes itself from siblings by explicitly labeling it as a demo and not a Sphere product, and by pointing to marketplace_services as the real catalog. This makes the tool's purpose unmistakable and distinct from the marketplace siblings.

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 guidance: it tells the agent this is demo-only and not a real product, and it directs the agent to marketplace_services for the real catalog and marketplace_x402_payment to purchase. This clearly indicates when not to use this tool and what alternatives exist, leaving no ambiguity about its appropriate context.

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 burden. It discloses that acceptance starts work, is free, and leads to payment upon completion. It also notes the need for credentials from marketplace_register. It does not mention failure modes or idempotency, but covers the core behavioral aspects adequately.

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 sentences. The first front-loads the action and consequence, the second lists requirements. No filler 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?

Given the tool's simplicity (three string params, no output schema), the description covers the essential usage: role, action, requirements, and payment terms. It omits details about return value or error handling, but these are not critical for a basic accept operation.

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 no parameter descriptions, so the description must compensate. It mentions all three parameters and clarifies that api_key comes from marketplace_register, but does not explain agent_id or contract_id beyond their existence. This partial coverage earns a 3.

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 verb 'accept', the resource 'contract', the role 'as the contractor', and the consequences 'start work' and payment. It distinguishes itself from sibling marketplace tools by specifying the contractor role and acceptance action, making it 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 implies usage context: when you are a contractor with an offered contract, you accept it. It mentions prerequisites (registration) and that it's free. However, it does not explicitly name alternative tools or exclusion criteria, so it's clear context but lacks explicit when-not 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 behavioral burden. It discloses the core action (releasing escrow and paying), the cost implications ('Free for the buyer; Sphere's commission is taken from the contractor's payout'), and authentication needs. It does not mention irreversibility or return behavior, but the main behavioral and financial consequences 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?

Two sentences with no wasted words. The primary action is front-loaded, followed by cost and authentication details. 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 a simple 3-string-parameter action with no output schema, the description covers the essential context: trigger, financial effects, and required credentials. It does not describe the return value or post-completion state, but the essential calling context is present. A slightly stronger warning about irreversibility would make it 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 has 0% description coverage, so the description must compensate. It names all three required parameters and adds useful provenance for api_key ('from marketplace_register'). However, it only lists agent_id and contract_id without further explanation, relying on self-evident names rather than fully defining their semantics.

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: 'Release the escrow and pay the contractor once you accept the delivered result.' This clearly states the tool's function and differentiates it from siblings like marketplace_accept_contract or marketplace_deliver_contract by focusing on final payment after acceptance.

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 a clear condition for when to use the tool: 'once you accept the delivered result.' This implies the correct workflow position after delivery and acceptance. It does not explicitly name alternatives or exclusions, but the trigger is specific enough for an agent to select it appropriately among siblings.

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 behavioral burden well. It discloses that payment comes from the funded balance, that collateral is refundable, and that the reply returns the exact amount. It could say more about failure modes or the contract's lifecycle, but the key monetary side effects are transparent.

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 and front-loaded: the action is stated first, then payment behavior, then required parameters. Every sentence contributes useful information with no filler.

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 the main purpose, payment, and key inputs, but it is incomplete for a 5-parameter tool with no annotations and no output schema. The task_payload structure and deadline_hours semantics are left undocumented, and the agent gets no guidance on what the returned contract looks like beyond the payment amount.

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 adds useful meaning for api_key and service_id by pointing to marketplace_register and marketplace_services, and it mentions task_payload. However, it omits deadline_hours entirely, does not describe the shape of task_payload, and says task_payload is required even though the schema marks it optional.

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 that this tool orders a service from marketplace_services Syndesus, using a specific verb and resource. It does not explicitly contrast itself with sibling tools like buy_* or marketplace_x402_payment, but the marketplace_services reference and contract lifecycle make the purpose reasonably distinct.

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: use this when ordering a service found in marketplace_services, and it states prerequisites like funded balance and credentials. It does not explicitly name alternatives or provide when-not-to-use guidance, but the usage context is clear enough for an agent.

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 so well: it discloses that the delivery must pass Sphere's gate before the buyer can see it, states that delivery is free, and identifies the credential source. It does not explain what happens if the gate rejects the delivery or whether delivery can be revised, but the disclosed behavior is substantive.

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 tight sentences: the core action and gate behavior come first, cost follows, then the parameter requirements. No filler, no repetition of schema types, and every sentence contributes useful guidance.

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 four-parameter mutation tool with no output schema, the description covers what to pass, which contract to target, the credential source, the gate constraint, and the cost. It does not explain response semantics on success or gate failure, but an agent has enough information to 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?

The schema has 0% description coverage, so the description must compensate. It does: api_key is tied to marketplace_register, contract_id is the accepted contract, result_payload is the delivered result, and agent_id is listed as required. It does not detail the expected shape of result_payload, so it is not perfect, but it adds real meaning beyond the raw 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 states a specific verb and resource: 'Deliver the result for a contract you accepted,' and adds a meaningful qualifier about Sphere's gate. This clearly separates it from sibling tools such as marketplace_complete_contract, marketplace_get_result, and marketplace_create_contract without needing to inspect their schemas.

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 a clear usage context: it is for contracts already accepted, and it points out that api_key comes from marketplace_register. It does not explicitly name alternatives or list when not to use the tool, so it misses the highest bar, but the context is far from vague.

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 full burden of behavioral disclosure. It explicitly says 'Free, no extra charge', which discloses cost, and uses the verb 'Check', which strongly implies a read-only operation with no side effects. It also hints that the tool only returns information (status, escrow, result availability) rather than causing changes. While it doesn't explicitly state 'does not modify anything', the language is clear enough for a simple query tool.

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, with the main purpose stated first and requirements after. The slight redundancy in 'Free, no extra charge' is minor but costs a tiny bit of conciseness. Overall, every sentence earns its place and the structure is 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?

The tool is simple: three string parameters, no output schema, no nested objects, no annotations. The description covers what the tool does and what inputs are needed, and it implies the output content by naming status, escrow, and result availability. It does not explicitly describe return values or error conditions, but given the low complexity, the description is adequate for an agent to call 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 adds meaningful context by stating which parameters are required and specifically notes that api_key comes from marketplace_register, which is useful provenance information. The parameter names themselves are self-explanatory (agent_id, api_key, contract_id), and the description confirms their role. It does not fully elaborate each parameter, but for such simple string types, this is sufficient compensation.

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 a specific verb ('Check'), a specific resource ('one of your contracts'), and the exact information it provides (status, escrow, result availability). This distinguishes it from related siblings like marketplace_get_result, which retrieves the result itself, and marketplace_my_sales, which lists contracts.

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 context: it is for checking your own contracts, including their status, escrow, and result availability. It also states the required credentials and their origin ('api_key from marketplace_register') and adds that there is no extra charge. It does not explicitly name alternative tools or conditions for when not to use it, but the purpose is distinct enough that an agent can infer when this is the right tool.

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 of behavioral disclosure. It states that the tool 'returns' the result, implying a read-only operation with no side effects. It also discloses a financial aspect ('Free once the contract is yours') and a security feature (Sphere's signature) that adds trust verification. It does not explicitly state 'does not modify anything,' but the language strongly implies a non-destructive get. It also specifies a precondition (status=delivered), which is useful behavioral context. This goes beyond a minimal statement of purpose.

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 compact paragraph that front-loads the primary purpose ('Verify what you bought') and then explains the output, usage timing, and requirements. It avoids redundancy and includes only relevant details. It is slightly longer than strictly necessary but each sentence contributes value—purpose, output, usage order, and prerequisites. The structure is logical and efficient.

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 three-parameter tool with no output schema, the description covers the essential aspects: what it returns (delivered result, contract hash, signature), when to call it (after status=delivered), and what prerequisites exist (agent_id, api_key, contract_id). It also mentions the purpose (verification) and cost (free after ownership). While it doesn't describe error handling or edge cases (e.g., what if contract not yet delivered), the precondition 'status=delivered' implies that it should be called only then. Given the tool's simplicity and the absence of an output schema, this is a complete enough description for an agent to use it 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?

The schema has zero description coverage, so the description must explain the parameters. It explicitly mentions all three required parameters: 'Requires agent_id + api_key (from marketplace_register) and contract_id.' It clarifies the source of api_key (from marketplace_register) and implies that contract_id identifies the specific contract whose result is being fetched. This adds meaning beyond the bare parameter names, though it doesn't provide formats or validation rules. It adequately compensates for the schema's lack of descriptions.

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 purpose: 'Verify what you bought: returns the delivered result of one of your contracts together with its contract hash and Sphere's signature.' It names a specific verb ('verify', 'returns') and resource ('delivered result of one of your contracts'), and it distinguishes itself from siblings like marketplace_get_contract (which presumably returns contract metadata) by focusing on the delivered result and verification artifacts. The purpose is unambiguous and unique among the listed siblings.

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 sequencing: 'Call after status=delivered, then marketplace_complete_contract to release payment.' This gives a clear when-to-use condition and the order relative to other marketplace tools. It also notes 'Free once the contract is yours,' implying ownership as a prerequisite. While it doesn't explicitly list alternatives or say 'use this instead of X,' the timing and context are clear enough for an agent to decide when to invoke it.

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?

Since no annotations are provided, the description carries the burden. It discloses that the operation is free and requires authentication, and it references a public ledger. However, it does not explicitly state whether this is a read-only operation or mention any side effects, limits, or return format. The verb 'see' implies read-only, but that is implicit.

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 plus a parenthetical that clarifies the auth requirement. It is front-loaded with the core function and includes only necessary context. There is no fluff or 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 read-like tool with no output schema, the description covers the essential aspects: purpose, required parameters, cost, and data source. It does not describe the output shape or error conditions, but these are not implied by a schema. Given the tool's low complexity, the current level of detail is nearly 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?

With 0% schema coverage, the description compensates by explaining the purpose of both parameters: agent_id identifies the seller and api_key comes from marketplace_register. This adds practical meaning beyond the bare schema types. It could specify formats or constraints, but it is sufficient for an agent to understand what values to provide.

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 specific action: viewing sold items/credit entries on the marketplace ledger. It clearly distinguishes itself from siblings like marketplace_my_services by focusing on sales/income tracking. The phrase 'so a seller can watch income' reinforces the 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 a prerequisite (requires agent_id + api_key from marketplace_register) and notes the tool is free, but does not explicitly say when to use this tool versus alternatives such as marketplace_my_services. The context implies it is for viewing sales rather than services, but that is not stated explicitly.

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 must carry the behavioral disclosure burden. It does so by implying a read-only operation ('See'), declaring that the call is 'Free', and stating the auth requirement ('agent_id + api_key'). It does not explain error behavior or exact output shape, but for a simple read tool this is reasonably transparent.

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 with no wasted words. It front-loads the core function, then adds cost and auth details, making it easy for an agent to parse quickly.

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 two-parameter read-only tool with no output schema, the description covers the key concerns: what the call returns (services and prices), why to call it (confirm a listing is live), cost, and authentication. It is missing only minor details such as error handling or listing-status formatting, which are not critical for a tool of this 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 description coverage is 0%, so the description must compensate. It does by identifying both required parameters and, importantly, noting that they come 'from marketplace_register', giving the agent a concrete source for the credentials. It could add more per-parameter detail, but the provenance clue is valuable.

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 ('See'), a clear resource ('the services you offer and their prices'), and states the intended use ('to confirm a listing is live'). It clearly distinguishes this from sibling tools like marketplace_my_sales and marketplace_services by emphasizing the agent's own offerings and pricing.

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 a clear use context: checking that one of your own marketplace listings is live. It does not explicitly name alternatives or when-not-to-use, but the purpose is specific enough that an agent can select it appropriately among the marketplace siblings.

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 behavioral burden and does a solid job: it discloses public visibility, no approval, free listing, and the authentication requirement. It does not fully detail update semantics (e.g., overwrite behavior or service_name uniqueness), but it provides meaningful behavioral context beyond a simple mutation statement.

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 tight sentences front-load the core purpose and then add high-value behavioral details (free, no approval, public, auth). There is no filler or repetition of schema 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?

The rich 100%-covered schema handles parameter meaning, and the description adds essential operational context: purpose, public visibility, no approval, and required credentials. The main missing pieces are the response format and explicit update semantics, but for this complexity the definition is largely 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?

All six parameters are already described in the input schema, so the description adds no new meaning beyond naming the key fields in the first sentence. This meets the baseline for a tool with full 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?

The description uses a specific verb ('publish or update') and clearly identifies the resource ('one of your own services in the public catalogue') along with the relevant fields. It also distinguishes itself from sibling tools by emphasizing ownership and public catalogue placement, 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?

It gives useful context ('Sell your work', free, no approval, public) and mentions the required auth from marketplace_register, but it does not explicitly say when to use this tool instead of related siblings like marketplace_my_services or marketplace_services. The usage is implied rather than directly contrasted with 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?

With no annotations, the description carries the full burden and does well: it discloses the one-time display of the api_key, the returned fields, the lack of approval/KYC, and that it is the only setup step. This goes beyond the schema and gives an agent critical operational 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?

Two dense sentences, no filler, front-loaded with the core action. Every clause adds useful information: purpose, conditions, return values, and a caution about the key.

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 registration tool with no output schema, the description covers the key operational facts: what is returned, the one-time secret, and where it fits in the contract workflow. The main gap is the undocumented agent_name parameter, but overall it is nearly 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 0% and the description never mentions agent_name or what value it should take. The parameter name is self-explanatory to a degree, but the description adds no meaning beyond the raw schema, failing to compensate for the low 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?

States a specific verb and resource ('Get an API key') and gives the purpose ('so you can order or deliver work'). It also names the returned values and positions itself as the only setup step for contract tools, clearly distinguishing its role among sibling 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?

Says when to use it: before using contract tools, and gives strong contextual signals ('Free, instant, no human approval and no KYC'). It doesn't explicitly name alternatives or exclusions, but no direct alternative exists among siblings, so the guidance is sufficient.

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 behavioral disclosure burden. It adds valuable traits: 'Free, no key and no registration' and the price-based filtering behavior. It does not mention the return format or potential pagination, but for a simple catalog listing these omissions are minor. The disclosed traits go beyond what the empty schema provides.

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 with no wasted words. The primary purpose is front-loaded, and the next-step guidance follows naturally. Every clause contributes value, from the scope ('every published service') to the cost/access statement ('Free, no key and no registration') to the routing to sibling tools.

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 zero-parameter, read-only catalog tool with no output schema, the description is complete. It tells the agent what it will get (services, descriptions, prices), the access requirements (none), and what to do after. No critical information needed to invoke or interpret the tool is missing.

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 per the rubric the baseline is 4. The description adds no parameter information because none exist. It correctly explains the output semantics (what services are listed) which is the only relevant semantic detail.

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: 'See what you can buy right now: every published service, what it does and its price'. It uses a specific verb ('see') and resource ('every published service'), and distinguishes itself from siblings by framing it as the starting point before creating a contract or paying per call. This leaves no ambiguity about what the tool does.

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 says 'Start here' and then directs the user to either marketplace_create_contract or marketplace_x402_payment for next steps. It also clarifies a key filter ('a service without a price is not listed'), which helps the agent know what to expect. This is strong when-to-use guidance with clear 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?

With no annotations provided, the description carries the full burden. It discloses the payment amount, network, need for signing an EIP-3009 authorization, and the absence of registration/API key. It does not explicitly mention refunds or failure modes, but given it's a payment tool, the essential behaviors are well 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 dense but every sentence contributes: it states the core offer, the two-step payment process, and the optional parameter. It is front-loaded with the essential purpose and avoids redundancy, making it efficient for an agent to parse.

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 there is no output schema, the description adequately states the result (verified result and signed receipt) and the payment terms. It lacks explicit details about the receipt format or potential errors, but for a transactional tool, it provides sufficient context for an agent to understand the expected outcome.

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 already covers all parameters (100% coverage), and the description adds critical context: x_payment is from a previous 402 reply, service_name defaults to sphere_receipt, and task_payload is input for the chosen service. This exceeds the schema's descriptions and clarifies the overall flow.

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: buying one verified result via x402 payment, with explicit details on cost (0.05 USDC on Base) and the two-step interaction. It also distinguishes itself from siblings by focusing on the x402 payment mechanism rather than a specific service.

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 usage instructions: first call without x_payment to receive payment terms, then sign and call again with x_payment. Also explains the optional service_name parameter for selecting a shelf service. This gives the agent a clear workflow and distinguishes when to use this tool.

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