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

The description discloses key behaviors beyond the readOnlyHint annotation: it returns 'last known balance' from a credential store, performs no network request, and explains the condition for the 'stale' flag (updated more than 5 minutes ago). This adds meaningful context that annotations alone don't provide.

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 deliver all essential information: the action, the caching behavior, and the staleness rule. Every sentence earns its place with no redundancy or 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 one-parameter tool with no output schema, the description explains the return concept (balance and stale flag) sufficiently well. It stops short of detailing the full response structure or edge cases (e.g., no cached value), but given the simplicity, this is a minor 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 description coverage is 100% and the only parameter 'origin' already has a clear description with a URI format and example. The description adds no additional parameter-specific meaning, so the baseline of 3 is appropriate.

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: 'Check cached credit balance for a server.' It distinguishes this tool from siblings by emphasizing that it uses a cached value and makes no network request, which sets it apart from other l402 tools like l402-fetch or l402-pay.

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 implies when to use this tool: when you want a fast, cached balance check without network overhead. However, it doesn't explicitly name alternatives or state when not to use it, so it lacks explicit exclusions that would merit a 5.

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

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

Annotations already flag destructiveHint=true and openWorldHint=true, so the safety profile is handled. The description adds the mode behavior and the toll-booth restriction, but it does not clarify side effects of a purchase, such as spending funds, irreversibility, or error/response 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 short sentences front-load the purpose and immediately state the key branching behavior. Minor redundancy exists between 'from a toll-booth server' and 'Only works with toll-booth servers,' but overall it is tight.

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 three-parameter tool with no nested objects, core invocation is covered: required URL, optional method, optional amountSats, and the toll-booth constraint. However, there is no output schema and the description does not say what a successful purchase or tier-discovery response contains, which is a notable gap for a financial 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 the baseline is 3. The narrative about omitting/providing amountSats adds a little clarity, but it largely repeats the schema's description of amountSats and does not enrich method or url beyond what the schema already says.

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

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

The description opens with a specific action ('Buy credits') and identifies the resource ('a toll-booth server') and a differentiator ('volume discounts'). It distinguishes this from sibling payment tools by restricting it to toll-booth servers, though it never names a sibling 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?

Provides explicit branching guidance: omit amountSats to discover tiers, provide amountSats to buy a specific tier, and only works with toll-booth servers. This gives clear when-to-use context, but it does not compare against siblings such as l402-pay or l402-discover, so it falls just short of a 5.

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

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

Annotations declare readOnlyHint=true, which the description aligns with by using 'Introspect'. The description adds value beyond the annotation by revealing what kind of read-only data is returned: wallet configuration, spending limits, and credential count. No hidden mutation or side effects are suggested.

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. The first sentence states exactly what the tool does and its outputs; the second gives actionable usage guidance. Every clause 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?

With no parameters and no output schema, the description sufficiently explains what the tool returns at a categorical level. It could be more explicit about output format or whether any setup is required, but for a zero-input introspection tool it is adequately complete for an agent to call 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 tool has zero parameters, so there is no schema burden to compensate for. The description accurately describes the tool's no-input introspection behavior, and the baseline of 4 is appropriate since no parameter documentation is needed.

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?

Description uses specific verb 'Introspect' with resource 'payment capabilities' and enumerates concrete outputs: wallets configured, spending limits, stored credential count. The instruction to call this first also distinguishes it from sibling tools like l402-pay or l402-fetch, making its role clear.

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

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

It explicitly says 'Call this first to understand what payment methods are available', giving clear context for when to invoke it. It does not explicitly list alternatives or when not to use it, but the sequencing guidance and broad discovery purpose sufficiently differentiate it from 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?

The readOnlyHint annotation already marks it safe, and the description adds genuinely useful behavior: balances are cached and possibly stale, and the lastUsed timestamp is the way to judge freshness. This is beyond the annotation and gives the agent a realistic expectation of data reliability. No contradiction exists.

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 action and displayed fields, then add the stale-balance caveat. Every sentence carries operational value, and no redundant filler is present.

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 listing tool, this description is complete: it says what is listed, what fields are shown, and warns about cache freshness. The lack of an output schema is mitigated by naming the visible fields, and there are no params/options whose behavior would need elaboration.

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 input schema is empty (0 parameters), so there are no parameter semantics for the description to enrich. With schema coverage at 100%, the description cannot add anything parameter-related, and the baseline of 4 applies.

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 the action ('List all stored L402 credentials') and the resource/scope precisely, then names the displayed fields (origin, cached credit balance, server type). This distinguishes it from siblings like l402-store-token or l402-balance by focusing on stored credentials rather than operations or current balance.

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

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

Usage is only implied: an agent can infer this is for inspecting stored credentials, and the 'cached/may be stale' caveat hints that l402-balance might be the alternative for fresh numbers. However, it never explicitly states when to prefer this tool or names an alternative, so it stops short of clear routing 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 readOnlyHint=true and openWorldHint=true already present, the description adds meaningful behavioral details: no payment is committed, the challenge is cached for later reuse, and responses include pricing and payment-method information. It does not contradict the annotations and gives enough context for safe usage.

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 core action appears first, followed by return-value highlights and the caching behavior. Every sentence earns its place without fluff 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?

For a simple probe tool with one required parameter and no output schema, the description covers what the tool returns, when to use it, and the relevant caching side effect. It does not specify failure behavior or non-L402 endpoints, but those are minor gaps given the overall clarity.

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 schema already documents both parameters and their defaults. The description reinforces that 'url' is the endpoint being probed but adds little about 'method' beyond what the schema provides. Baseline 3 is appropriate.

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 ('Probe') and resource ('endpoint') and states the purpose: discover L402 pricing without payment. It also names concrete outputs (cost in sats, payment methods, credit tiers) and distinguishes itself from l402-pay by mentioning challenge caching. This makes the tool's role clear even among many 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 clearly implies the tool is a pre-payment discovery step: 'without committing to payment' and 'a subsequent l402-pay can reuse it' provide strong context for when to use it. It does not explicitly enumerate exclusions or alternative tools, but the intended workflow is evident.

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

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

Annotations declare openWorldHint and destructiveHint, so the description adds value by explaining the payment side effects, credential reuse, untrusted response bodies, and the maxCostSats cap. It doesn't fully detail what happens to stored credentials or whether failures are reversible, but it covers the key behavioral traits beyond annotations.

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 well-organized, front-loading the core fetch-and-pay behavior before edge cases. Every sentence adds information, though the x402 and widget-host sentences could be seen as slightly crammed. Overall it earns its length.

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 complex tool with 9 parameters, no output schema, and payment side effects, the description covers the main flows, the autoPay decision, the preview routing, and the untrusted-content warning. It doesn't specify the exact return shape of a 402 response, but the description says the price and paymentHash come back, which is enough for an agent to proceed.

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. The description adds meaning by explaining the relationship between maxCostSats and MAX_AUTO_PAY_SATS, the purpose of pubkey for sharing credentials, and the txHash retry behavior. It doesn't describe every parameter in prose, but the schema already does that.

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

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

The description clearly states the tool fetches a URL and handles HTTP 402 payment challenges, distinguishing it from siblings like l402-pay and l402-fetch-preview. It names the specific protocols (L402, IETF Payment, Cashu, LNURLcash) and the autoPay behavior, so an agent can tell exactly what this 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?

The description explicitly explains when to use autoPay vs not, when to call l402-fetch-preview first for widget hosts, and when to use l402-pay for a returned 402. It also mentions x402 experimental format handling. This is strong routing guidance relative to 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?

Annotations already declare readOnlyHint=true, so the description's claim of 'without spending any sats' reinforces but adds specific meaning (no financial side effect). It also describes what the tool returns (cost, protocol, payment method) and the intended UI usage, which goes beyond the annotation. However, it does not mention potential errors or connection issues, a minor gap given the annotations cover safety.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the primary purpose, and no filler. The usage guidance is embedded efficiently. Every clause 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 preview tool with read-only annotations, the description covers the core purpose, return data, and usage context. It does not describe the exact output schema (since none exists), but that is compensated by stating the key fields. Minor gaps like error handling or authentication requirements are not addressed, but given the simplicity, it 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?

Schema description coverage is 100%, so each parameter is already documented. The description adds no parameter-specific usage detail beyond what the schema provides. It does not explain how to format arrays or headers, but the schema already covers that. Thus, baseline 3 is appropriate.

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 ('Preview'), resource ('payment requirements for a URL'), and outcome ('without spending any sats'). It clearly distinguishes from l402-fetch by positioning itself as a pre-check. The purpose is unambiguous and actionable.

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 instructs to 'Use this before l402-fetch' and gives the condition (to give the user a chance to approve or cancel payment). Also mentions the widget host context. This directly routes the agent to the correct tool and tells when not to use the alternative.

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

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

Annotations already flag destructiveHint and openWorldHint, but the description adds substantial behavioral detail: it stores credentials for the next fetch, polls the payment page for up to 120s for human wallets, and requires human approval for unrelated invoices. No contradiction with annotations.

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 dense, purposeful sentences: the core action and effect come first, followed by the human-wallet polling behavior and timing, then the approval condition. There is no filler or redundant restating of schema content.

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 payment tool with no output schema, the description provides rich context: source of the challenge, credential storage, polling window, and human approval rule. The only minor gap is that it does not state what the caller receives on success, failure, or timeout.

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 schema already documents all four parameters, including the paymentHash/invoice relationship and the human-approval caveat. The description reinforces these ideas but adds no new parameter-level format or constraint details 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 opens with a concrete verb-object pair: 'Pay a challenge ... by its paymentHash.' It names the exact source tools (l402-fetch or l402-discover), making it clearly distinct from payment-adjacent siblings like l402-buy-credits or l402-redeem-cashu.

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 timing guidance ('call it straight after showing the payment URL') and restricts automatic payment to challenges from l402-fetch or l402-discover. It does not explicitly list when to prefer an alternative payment sibling, so it falls just short of full routing 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?

Annotations only provide openWorldHint=true and destructiveHint=false, but the description adds substantial behavioral detail: auto-pay to the service is paused while unresolved, settled payments store credentials when possible, failed payments are cleared, and abandon requires human approval. This is far beyond what the annotations alone convey.

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 dense paragraph with the core purpose front-loaded, followed by invocation modes and parameter-specific behavior. Every sentence earns its place; there is no filler or repetition of schema 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?

Given three optional parameters, no output schema, and significant side effects, the description covers invocation modes, resolution outcomes, credential storage, and the human-in-the-loop requirement. It does not describe the return format of listing unresolved payments, but this is a minor gap for an agent already given the schema.

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%, but the description adds real meaning beyond the schema: paymentHash triggers an NWC lookup_invoice or Cashu mint lookup, preimage must hash to the payment hash to settle, and abandon requires human confirmation. It enriches each parameter with behavioral context rather than repeating schema text.

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: 'Resolve a payment whose outcome is unknown' and immediately distinguishes the two main modes: listing unresolved payments versus resolving a specific one. This clearly separates it from siblings like l402-pay or l402-fetch by focusing on reconciliation of uncertain payments.

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 explicit call patterns: call with no arguments to list, with paymentHash to query the wallet, with preimage to settle, or with abandon for human confirmation. It does not explicitly name sibling alternatives or state when not to use the tool, but the usage conditions are 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?

Beyond the annotations, the description reveals an important behavioral trait: it automatically handles the two-step flow of creating an invoice then redeeming the token. It also clarifies that the tool only works against toll-booth servers. It does not detail the destructive consumption of the Cashu token, but destructiveHint=true already signals the mutation risk.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loaded with the core purpose, and contains no fluff. The only minor inefficiency is repeating the toll-booth-server constraint in both the first and final 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 tool with no output schema, the description covers the main selection criteria, the target server type, and the internal two-step flow. It does not specify return values or post-redemption behavior, but the annotations and simple parameter surface make this a minor gap rather than a blocking one.

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 input schema already documents both parameters with 100% coverage, so the baseline is 3. The description adds contextual flow details but no additional parameter-level meaning 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 opens with a specific verb and resource: 'Redeem Cashu ecash tokens directly on a toll-booth server', and adds a clear differentiator by noting it avoids the Lightning round-trip. It also closes with a scope limitation ('Only works with toll-booth servers'), making it easy to distinguish from siblings like l402-pay or l402-fetch.

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 useful context for when to choose this tool: it is for direct Cashu redemption on toll-booth servers, avoids Lightning, and automates the two-step flow. It does not explicitly name alternative sibling tools or state 'use X instead', but the toll-booth-only constraint and direct-vs-Lightning framing provide adequate selection 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?

Annotations declare readOnlyHint and openWorldHint, so the read-only nature is already known. The description adds useful behavioral context beyond annotations: filters are sent to relays, query text is matched locally, and announcement content is untrusted. This is meaningful additional context for an agent.

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 concise sentences that front-load the core purpose, add relevant filtering mechanics, and include an important trust caveat. There is no redundant or filler content.

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, the description adequately states what the tool returns ('URLs, pricing and capabilities') and covers key behavioral details like local matching and untrusted content. It is not exhaustive, but it provides enough for an agent to select and invoke the tool correctly.

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

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

Schema description coverage is 100%, so parameters are already well-documented by the schema itself. The description adds related context, such as local matching of query text and relay-side filtering, but does not significantly expand on the parameter semantics 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 clearly identifies a specific action ('Search Nostr relays for paid API announcements (kind 31402)') and the returned content ('URLs, pricing and capabilities'). It does not explicitly distinguish this from sibling tools like l402-discover, so it falls short of full sibling differentiation.

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

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

The description provides clear context for when this tool is appropriate: searching Nostr relays for paid API announcements. It does not explicitly name alternatives or exclusions, but the use case is specific enough for an agent to understand 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?

The description adds behavioral context beyond the idempotentHint annotation by stating the token is persistently 'stored as a credential' and that this makes subsequent l402-fetch calls authenticated. It does not contradict the annotations; the readOnlyHint=false aligns with the mutation implied by 'Store.'

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no wasted words. It front-loads the core action, then provides the usage trigger and downstream benefit, 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 store operation, the description covers what the token is, where it comes from, and why it matters. It does not describe the return value or error behavior, but given the simple side-effect model and the idempotentHint annotation, this is a minor gap rather than a blocking omission.

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 input schema already has 100% coverage with clear descriptions for both parameters, including the token format 'macaroon:preimage'. The description reinforces the token format and purpose but does not add meaningfully beyond the schema's parameter 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 states a specific verb and resource: 'Store an L402 token (macaroon:preimage) obtained from a payment page.' It also clarifies the token's role as a stored credential for authenticating subsequent l402-fetch calls, making the purpose unambiguous and distinguishable from sibling tools like l402-credentials or l402-fetch.

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 an explicit trigger: 'Use this when a user pastes back a token from a toll-booth payment page.' It also explains the downstream effect by noting the token is stored for later l402-fetch authentication, but it does not explicitly mention alternatives or cases where this tool should not be used.

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