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 behavioral load, and it does disclose the key non-obvious trait that no call is proxied and credentials stay with the caller. It also enumerates the returned per-server fields (product surface, auth model, transports, docs URL), though it omits read-only confirmation, auth requirements, and pagination 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 tight sentences, front-loaded with the scope, then payload, then filter, then the critical no-proxy caveat. No filler and nothing redundant.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-optional-param discovery tool with no output schema and no annotations, the description supplies what an agent needs: the listed resource, the fields of each entry, the filter, and the non-proxy guarantee. Remaining gaps (read-only confirmation, pagination) are minor.

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% and the single parameter's meaning is already documented. The description adds only 'Optional q filters by name/product/summary', which largely restates the schema's 'case-insensitive substring over name/product/summary', making this baseline-3 territory.

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 ('List every u.cash MCP server in the fleet') and enumerates the sub-fleets (buyer, seller, prime, legacy) plus the per-server payload. It is distinguishable from the closely named sibling uxc_discover_tools by scope (servers vs tools), but it never names that sibling or draws the line explicitly.

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 clear operational context: it is 'Discovery only' and the caller must 'connect to each server directly with your own credentials; no call is ever proxied', which tells an agent what this tool is not for. It stops short of explicitly routing between this and a named alternative such as uxc_discover_tools.

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

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

With no annotations, the description carries the full burden and does well: it discloses case-insensitive substring matching, optional server scoping, returned fields, and that no call is proxied. It does not cover authentication needs, rate limits, or pagination behavior, 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?

The description is three tight sentences with no wasted wording. It front-loads the search behavior, then returns, then the discovery-only constraint.

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, but the description explains what is returned: the tool, a one-liner, its server, and how to connect. It also covers the critical discovery-only/no-proxy behavior, making it complete for an agent to use 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 67%, and the description adds useful semantics for q by specifying case-insensitive substring matching and for server by describing scope. However, it does not explain the limit parameter beyond the schema's default/min/max, so it only partially compensates 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?

The description states a specific verb and resource: search tools across every u.cash MCP server by name or description. It clearly distinguishes itself from uxc_discover_servers by focusing on tools rather than servers, and from catalog/order operations in the sibling list.

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 usage context: optional server scoping and the explicit instruction to connect to the discovered server directly rather than proxying calls. It does not explicitly name alternatives like uxc_discover_servers or uxc_search_catalog, so it stops short of full when-to-use guidance.

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

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

With no annotations, 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?

With no annotations, the description carries the full burden: it discloses that the catalog is public and key-free and lists the returned fields, which is genuine behavioral context. It omits pagination behavior, result ordering, rate limits, and what happens with large result sets — meaningful gaps for an unannotated read 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?

Two compact sentences, front-loaded with the resource and scope, then the filter and field list. No filler, though the parenthetical field enumeration is dense and slightly list-like.

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, so the inline field list usefully compensates by describing the return shape. But with no annotations and an undocumented limit parameter, the description leaves pagination and result-size behavior unspecified, which an agent calling a broad market listing would want.

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 67%, so the baseline is 3. The description repeats the schema's own q description ('filters by title/merchant/description') and says nothing about limit or the fields projection, so it adds no meaning beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific resource (the public cross-merchant market catalog of published checkouts) and enumerates the fields returned, so the agent knows exactly what it retrieves. However, it never distinguishes itself from catalog-adjacent siblings like search_catalog or lookup_products, so the agent must infer the difference.

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' signals the unauthenticated/public browsing case and 'every published checkout across merchants' implies a broad browse rather than a targeted lookup, which hints at when to use it. But there is no explicit when-to-use/when-not and no named alternative, 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?

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 auth requirement ('No key', PUBLIC) and the row-level payload (provider contact email, sendable asset code, price), but says nothing about pagination behavior, result volume, or rate limits despite a limit parameter existing.

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, front-loaded sentence that leads with the resource and appends the access constraint. The parenthetical is dense but informative; the 'No key.' fragment is terse yet earns its place by answering an implicit auth question.

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 annotations, so the description must do more. It partially covers the return shape (row fields) and access model, but omits pagination limits, expected volume, and any distinction from sibling catalog tools — leaving meaningful gaps for a catalog-listing 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 50%. The 'fields' parameter is thoroughly documented in the schema, but 'limit' has no description at all (no default/max explanation), and the description never mentions either parameter or the pagination semantics implied by limit. The description does not compensate for the undocumented 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?

The description names a specific resource — the public cross-provider services catalog — and clarifies its scope as public/no-key, which helps distinguish it from authenticated siblings like uxc_get_market or uxc_get_order. However, it never explicitly contrasts itself with retrieval siblings such as uxc_search_catalog or uxc_lookup_products, so the agent must infer the difference.

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 'No key' implicitly tells the agent this works without authentication, but there is no explicit when-to-use guidance or mention of alternatives (search_catalog, lookup_products, get_market). The agent is left to guess when this catalog is preferable to the other catalog-reading tools.

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

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

No annotations are provided, so the description carries the full behavioral burden. 'Public (no key)' is valuable context about authentication, but it omits whether the tool is read-only, rate-limited, or what the response format looks like. The auth transparency helps, but more is needed for a lookup 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?

Two very short sentences, well front-loaded with the core purpose. No wasted words, though the extreme brevity borders on under-specification given the tool's complexity.

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, no annotations, incomplete parameter documentation (cloud undocumented). The description gives only the bare minimum: what it does and that it's public. For a batch lookup tool with 3 parameters, this is incomplete.

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

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

Schema description coverage is only 33%, so the description must compensate. The 'ids' parameter is somewhat self-explanatory, but 'cloud' is completely undocumented in both schema and description, and 'fields' has schema documentation but no mention in the description. The description adds no parameter semantics beyond the tool's core purpose.

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: 'Batch catalog lookup by ids.' This is clear and distinguishes from the singular 'uxc_get_product' sibling by emphasizing batch mode. However, it doesn't explicitly name alternatives or clarify what 'catalog' encompasses relative to search_catalog.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Implies usage via 'batch' and 'by ids', but provides no explicit when-to-use guidance or exclusions. An agent must infer that this tool is for multiple known IDs versus uxc_search_catalog for discovery or uxc_get_product for a single item.

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.