U.CASH Pay

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

With no annotations, the description carries the full burden. It discloses that no key is required and that cloud targets hosted merchants, but says nothing about reversibility, idempotency, what happens to the underlying order/payment, or error behavior for an already-completed session.

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 short sentences, front-loaded with the action and scope, with no filler. Every clause carries 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?

A mutation tool with no annotations, no output schema, and 0% schema description coverage needs more than two sentences. The identifier's meaning and the consequences of cancellation are 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?

Schema coverage is 0%, so both parameters are undocumented in the schema. The description partially compensates for cloud (hosted merchant) and the auth posture, but leaves id entirely undefined — whether it is a session ID, order ID, or checkout token is unstated.

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+resource ("Cancel a UCP checkout session"), which inherently distinguishes it from siblings like uxc_complete_checkout and uxc_create_checkout. It does not explicitly name alternatives, and "UCP" is unexplained jargon, so it falls short of a 5.

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 key; pass cloud for a hosted merchant" gives a conditional hint for the cloud parameter and the auth posture, but there is no guidance on when to cancel versus completing or abandoning a session, and no prerequisites or state requirements 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 the full burden and does disclose useful traits: no key required, ap2 is optional, cloud selects a hosted-merchant path, and the call drives a state transition to ready_for_complete. It omits what the call returns, whether it is idempotent, or what side effects occur on the session.

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 fragments, front-loaded with the core action and state outcome. Efficient, though the arrow notation and telegraphic phrasing sacrifice some readability.

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 annotations, no output schema, and one of three params undocumented. The description covers auth mode and a state transition but leaves return behavior and the required id's meaning unaddressed, so it is only minimally complete for a mutation-style 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 only 33% (only ap2 documented), so the description must compensate. It adds meaning for cloud ('for a hosted merchant') and clarifies ap2's optionality, but the required id parameter remains completely unexplained in both schema and 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 names a verb ('Mint payment challenges') and a resource (checkout session) plus a resulting state ('-> ready_for_complete'), but 'minting payment challenges' is oblique for a tool literally named complete_checkout. It does not distinguish itself from siblings like uxc_create_checkout, uxc_cancel_checkout, or uxc_verify_payment.

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 key; pass cloud for a hosted merchant' hints at an auth/hosting mode but gives no when-to-use versus alternatives. There is no guidance on prerequisites (e.g. session state required before completing) or on when ap2 should be supplied.

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 usefully discloses that no API key is required and previews the return shape ({id, status, currency, line_items, totals, ap2}), but says nothing about session lifetime, idempotency, failure modes, or what 'ap2' signifies. Partial disclosure of a mutation tool's behavior.

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 compact clauses, front-loaded with the core action, then the auth note, then the return shape. No filler sentences.

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 creation tool with no annotations and no output schema, the description supplies the return shape and auth hint, which covers a lot. However, session lifecycle, required preconditions, and the meaning of buyer/context/cloud remain undocumented, leaving real gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 60%, and the description adds little beyond restating the cart shape: 'multi-item' maps loosely to line_items and 'mixed-currency' to currency. The buyer, context, and cloud (merchant token) parameters get no semantic explanation in either the description or 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?

States a specific verb and resource ('Create a UCP checkout session') with scope qualifiers ('multi-item, mixed-currency cart', 'for a merchant catalog'), which clearly separates it from the get/cancel/complete checkout siblings. It does not explicitly name an alternative, so it stops short of the top band.

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 choose this over uxc_get_checkout, uxc_complete_checkout, or uxc_search_catalog, nor any stated preconditions (e.g., must line_items reference existing catalog items). The 'No key' fragment hints at an auth mode but is not framed as usage 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, the description carries the full burden. It usefully discloses the state machine (incomplete -> ready_for_complete -> completed) and that no auth key is required, which is real behavioral context. It does not state read-only behavior explicitly, error behavior for unknown ids, or rate limits, so disclosure remains partial.

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 front-loaded sentence with the resource and identifier first, then a compact parenthetical for the lifecycle and a short clause for auth/cloud. No filler sentences.

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 two-parameter fetch tool with no output schema, no annotations, and 0% schema coverage, the description covers identity, lifecycle, and auth context but omits what the response contains, error/not-found behavior, and the concrete value expected for 'cloud'. Adequate but with clear gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It explains both parameters at a high level: 'id' identifies the session and 'cloud' is passed for a hosted merchant. It still does not clarify expected formats (e.g., id shape, valid cloud values), leaving gaps the schema also fails to cover.

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 ('Fetch a UCP checkout session by id') and adds the lifecycle states, so an agent knows it retrieves an existing session rather than creating or completing one. It does not explicitly name a sibling, but the get/create/cancel/complete verb distinction makes it separable from uxc_create_checkout and uxc_complete_checkout.

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 key; pass cloud for a hosted merchant' gives a usage condition for the cloud parameter, and the status chain implies the tool is used to poll session progress. However, there is no explicit when-to-use vs. alternatives guidance (e.g., call this after uxc_create_checkout, before uxc_complete_checkout), so usage is only implied.

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

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

No annotations are provided, so the description carries the full burden. It usefully discloses the critical trait 'No key' (unauthenticated) and the public/global scope, but says nothing about rate limits, pagination behavior, result ordering, or empty-result handling for a list endpoint.

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?

A single tightly-packed sentence that front-loads the core identity (public market catalog) before listing fields and the q filter. Every clause earns its place 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?

Given no annotations, no output schema, and a 2-param tool with partial coverage, the description covers identity, scope, auth, and returned fields well enough to call. But it omits limit semantics and any list behavior (pagination), so an agent lacks enough to invoke it fully correctly beyond defaults.

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 50%: the q filter is documented identically in both schema and description, adding no new semantics. The limit param has no description anywhere; the description does not explain its default, maximum, or pagination implication, leaving half the parameters under-specified. Adequate, not additive.

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 (get) and resource (public cross-merchant market catalog), enumerates the returned fields, and distinguishes itself as PUBLIC with no key. An agent can tell it apart from sibling search/lookup tools immediately.

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?

Clearly conveys the use context: querying the public global catalog with no auth. It does not name an alternative sibling (e.g. uxc_search_catalog or uxc_lookup_products) or state when to prefer one over the other, so it stops short of full when/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, the description carries the full burden. It usefully discloses the auth profile ('No key') and the return content (per-item fulfillment status + fulfillment events), which is meaningful for a read tool, but says nothing about error cases, rate limits, or that the operation is strictly non-mutating.

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 compact sentences with the primary purpose front-loaded and the auth/hosting caveat trailing. No filler, though the parenthetical and the cloud note could be woven together more tightly.

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 annotations and no output schema, so the description must stand alone. It covers purpose, return content, and auth, but omits the meaning of 'id', any failure/error behavior, and how this differs from the sibling get_checkout, leaving gaps for a two-parameter 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 0%, so the description must compensate for both parameters. It gives partial meaning to 'cloud' ('pass cloud for a hosted merchant') but leaves the format/value unclear and says nothing at all about the required 'id' (what identifier namespace it belongs to), so half the parameters remain undocumented.

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 (View) and resource (UCP checkout session as an order), with a parenthetical clarifying the payload (per-item fulfillment status + fulfillment events). This distinguishes it reasonably from write-oriented siblings like uxc_complete_checkout, though it does not explicitly contrast with the close sibling uxc_get_checkout.

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 only guidance is an auth note ('No key; pass cloud for a hosted merchant'), which is really a parameter hint rather than when-to-use. It never says when to call this versus uxc_get_checkout or the other checkout siblings, leaving the main selection ambiguity unresolved.

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 does disclose the key behavioral fact that the endpoint is public and needs no auth, and that it returns a single product. However, it says nothing about rate limits, error behavior for unknown ids, or whether the response is cached or eventually consistent.

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 short clauses with zero waste, front-loading the core action and then the routing/auth guidance. 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?

Adequate for a simple two-parameter read tool with no output schema, but with 0% schema coverage and no annotations, the silent 'cloud' parameter is a real gap that the description should have closed.

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, and it does not. It names only 'id', leaving the 'cloud' parameter completely undocumented in both schema and prose, and it gives no format, type, or example for either parameter.

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+resource ('Fetch a single catalog product by id') and distinguishes itself from the sibling uxc_search_catalog, which is described as the id-discovery counterpart. An agent can tell which tool to use without opening the schema.

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?

Gives explicit when-to-use routing: pair with uxc_search_catalog to find ids. It also names the precondition that the operation is public, i.e., no key required. Nothing is left to inference.

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 burden. It usefully discloses the no-auth ('No key') requirement and the shape of each returned row, which are real behavioral facts. However, it says nothing about pagination behavior, result size, ordering, or rate limits for what is clearly a paged catalog read.

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?

A single dense sentence with the key qualifiers (PUBLIC, cross-provider, no key) front-loaded and payload details in a compact parenthetical. No filler, though the parenthetical return-field list is arguably doing schema work the tool never states elsewhere.

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?

There is no output schema and no annotations, so the description's enumeration of returned fields partially compensates and is the right instinct. It is still incomplete for a paged list tool: nothing explains the 'limit' parameter, default page size, or how to retrieve the remainder of the catalog.

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 on its single 'limit' parameter (default 50, max 200), and the description never mentions limiting, paging, or result size. The one parameter an agent must reason about is left entirely undocumented in both structured and prose form.

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 resource ('PUBLIC cross-provider services catalog') and even enumerates the row payload (provider contact email, sendable asset code, price), so an agent knows what it gets back. It does not distinguish itself from close siblings such as uxc_search_catalog, uxc_lookup_products, or uxc_get_market, which an agent could easily confuse it with.

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 key' hints that this is callable without authentication, but the description never says when to reach for this catalog versus uxc_search_catalog or uxc_get_market. There are no exclusions, prerequisites, or alternative-routing guidance, so selection is left to inference.

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

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

With no annotations provided, the description carries the full behavioral burden. Stating 'Public (no key)' is useful auth context, but there is no disclosure on rate limits, response shape, error handling for missing ids, or what 'cloud' implies. For a public read endpoint, the safety profile is inferable but incomplete.

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 terse sentences with zero waste. The core action is front-loaded and the public/no-key note is a compact qualifier. Nothing extraneous.

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 two-parameter tool with no annotations, no output schema, and 0% schema coverage, the description is too sparse. It omits what 'cloud' means, how missing ids are handled, and any return-value guidance. An agent would struggle to call 'cloud' correctly without further context.

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 both parameters ('ids' and 'cloud') are undocumented in structured data. The description only hints at 'ids' via 'by ids' and gives no meaning to 'cloud' – is it a region, a provider, a filter? The description fails to compensate for the coverage 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?

States a specific verb and resource ('catalog lookup by ids'), distinguishing it from the singular 'uxc_get_product' by its batch nature. Clear enough that an agent can tell it apart from search_catalog, though the two-char 'uxc_' prefix and lack of explicit sibling comparison keep it short of a 5.

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 word 'Batch' implies usage for retrieving multiple items at once, and 'by ids' implicitly contrasts with 'uxc_search_catalog', which presumably handles non-ID queries. However, no explicit when-to-use versus alternatives is given, leaving routing to inference.

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 does disclose a genuinely useful security fact the schema cannot convey: merchant identity comes from a cloud token or the platform default, and no API key is needed. However, it says nothing about read-only semantics, rate limits, empty-result behavior, or error conditions.

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 with no filler, and the core capability is front-loaded before the merchant-resolution detail. Efficient and readable, though the parenthetical parameter list reads a bit like a schema restatement.

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 4-parameter tool with 0% schema coverage, no annotations, and no output schema, the description covers the basics but omits the two things an agent most needs: the serialization format of 'filters' and 'pagination', and any sense of the result shape or paging behavior. Adequate to start, not sufficient to call confidently.

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 map all four parameters conceptually (query = text query, filters = price filters, pagination = pagination, cloud = token source), which is better than nothing. But it gives no encoding hints for the string-typed 'filters' and 'pagination' arguments, so an agent still cannot construct valid values from the description alone.

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?

Specific verb+resource: "Search a merchant catalog" with the sub-mechanisms named (text query, price filters, pagination). It is clear what the tool does, but it never distinguishes itself from the closest siblings, uxc_lookup_products and uxc_get_product, which sound like they also retrieve product data.

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 statement of when to reach for this tool rather than uxc_lookup_products, uxc_get_product, or uxc_get_market. Usage can only be inferred from the word "Search" plus the presence of filters, which is the minimum of implied guidance and leaves the agent guessing among near-identical 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 full burden and largely does so: it discloses that no seller key is required, that the challengeId identifies the resource, that settlement is gated by on-chain confirmation, and that the result is settled or pending. Missing are idempotency/retry semantics and error behavior for an unknown hash, so it is strong but not exhaustive.

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?

Front-loads the role tag 'BUYER-SIDE.', then moves precondition, parameters, and return values in four tight sentences with no filler. Every sentence adds 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?

There is no output schema and no annotations, yet the description still covers return states (settled/pending), the prerequisite chain, and the auth profile (no seller key needed). Only the exact hash format and retry/idempotency behavior are left unspecified, which are minor gaps for a two-parameter settlement call.

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 supply all parameter meaning, and it does: challengeId is tied to the accepts[] entry that was paid, and hash is the on-chain transaction hash. Neither parameter's expected format (hex encoding, length) is specified, but the semantic origin of both is explained clearly.

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+resource (submit a tx hash to settle a payment) and explicitly scopes it as 'BUYER-SIDE', which distinguishes it from the checkout/order siblings. It names the upstream sibling uxc_view_door and the accepts[] entry that produces the challengeId, so an agent can place it in the flow without opening any schema.

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?

Gives a clear precondition (you have already paid on-chain from your own wallet, using the challengeId from uxc_view_door) and the trigger for calling it. It does not state when NOT to use it or what to do if the payment already settled, but the sequencing guidance is concrete and unambiguous.

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

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

With no annotations, the description carries the burden and does reasonably well: 'No key' specifies no auth is needed, it enumerates the return contents (price, accepts[], seller receive address, exact amount), and clarifies that status=true polls settlement 'without minting a new challenge.' It omits rate limits or error behavior, but for a public read this is solid.

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?

Single dense paragraph that front-loads the core purpose before elaborating on return contents and the status mode. No filler sentences, though the run-on structure with parentheticals is slightly harder to scan than it could be.

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 two-parameter read tool with no annotations and no output schema, the description covers purpose, auth requirements, return shape, and the alternate status mode. Only edge behavior (what happens if the resource has no door, error cases) is left unaddressed.

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 50% (res_id undocumented in schema, status documented). The description compensates by tying both parameters to concrete behavior: res_id maps to the /r/{res_id} door, and status=true is explained as a no-mint settlement poll, adding meaning beyond the schema's terse 'poll mode' note.

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 ('Fetch the public 402 payment door for a resource') and names the exact URL semantics (https://agents.u.cash/r/{res_id}). It is clearly distinguishable from siblings like uxc_verify_payment and uxc_get_checkout because it describes what a buyer sees before paying.

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 routes usage: 'Use as a BUYER to see what to pay, then uxc_verify_payment after paying' names the correct follow-up tool and role. It also explains the status=true mode, but does not state when not to use it (e.g., seller-side checkout flows via uxc_get_checkout).

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