longwatch

Watch an x402 endpoint

watch_x402_endpoint

Monitor an x402 endpoint for downtime and changes to its payment challenge, price, network, scheme, or recipient. Target probes do not attach payment. Includes 7 days of polling. Costs $0.005 USDC per call via x402 (Base) — no API key, no account. Calling without payment returns 402 with the payment requirements. Free alternative: GET https://longwatch.dev/demo for a free NVDA Form 4 sample, or POST https://longwatch.dev/try for a 24h watch — no wallet needed.

Input Schema

TableJSON Schema

Name	Required	Description
`url`	Yes
`body`	No
`method`	No
`webhook`	No	optional HTTPS endpoint for signed push alerts; polling still works
`expected_scheme`	No
`idempotency_key`	No	unique retry key; the same key and input return the original watch
`expected_network`	No
`expected_amount_atomic`	No

TDQS

A4.2/5.0

Behavior5/5

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

No annotations were provided, so the description carries the full behavioral burden. It discloses that probes do not attach payment, unpaid calls return 402 with payment requirements, polling lasts 7 days, each call costs $0.005 USDC, and no API key/account is needed. This is strong behavioral disclosure for a paid x402-style tool.

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

Conciseness5/5

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

The description is front-loaded with the core monitoring behavior, then gives cost, auth posture, 402 behavior, and free alternatives. Each sentence adds operational value and there is no filler.

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

Completeness3/5

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 8 parameters, the description does a good job on payment flow but not a complete job. It does not explain what a successful response looks like, how to supply payment via x402, or how the optional request-shaping parameters like method/body/webhook/expected_* interact. These are material gaps for correct invocation beyond the happy-path url-only call.

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

Parameters2/5

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

Schema description coverage is only 25% and the description does not enumerate the individual parameters. It hints at domain concepts like price, network, scheme, and recipient, which loosely map to expected_amount_atomic, expected_network, and expected_scheme, but body, method, webhook, and idempotency_key receive little or no meaning beyond their names/schema stubs. For an 8-parameter tool, this is a clear gap.

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

Purpose5/5

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

Description opens with a specific verb and resource: 'Monitor an x402 endpoint for downtime and changes to its payment challenge, price, network, scheme, or recipient.' It also says 'Includes 7 days of polling,' which clearly distinguishes this watch-style tool from the check_* siblings, especially check_x402_endpoint. This is far beyond a tautology.

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

Usage Guidelines4/5

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

The description gives practical selection context: it costs money, needs no API key/account, includes 7 days of polling, and offers free alternatives when no wallet is available. It does not explicitly compare to check_x402_endpoint or other watch_* tools, but the '7 days of polling' language plus the free-trial alternative makes usage situation reasonably clear.

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

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TDQS

A3.7/5.0

Disambiguation4/5

Most tools are clearly separated into immediate check_* and persistent watch_* counterparts across distinct source types, plus lifecycle tools for creating, polling, and deleting watches. The generic check_now and create_watch overlap somewhat with the specialized check_*/watch_* tools, but the descriptions clarify session vs. persistent usage.

Naming Consistency4/5

The check_<source>/watch_<source> pairing is consistent across all six monitored source types, and lifecycle tools use predictable verb-based names like create_watch, delete_watch, poll_alerts, and try_watch. Minor deviations like check_now and create_watch rather than watch_create break the pattern slightly, but the overall convention remains legible.

Tool Count4/5

Eighteen tools is on the heavier side, but the count is justified by six source types each having both a check and watch mode, plus lifecycle operations. The generic check_now and create_watch add redundancy with the specialized tools, making the set slightly larger than strictly necessary.

Completeness3/5

The server covers immediate checks, persistent watches, trial watches, polling, and deletion, so the main monitoring workflow is present. However, there is no update_watch, list_watches, or get_watch status tool, so agents cannot modify or enumerate existing watches and must delete/recreate instead.

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