HTTP 428 precondition-required
https://agent-observatory-sensor.nolimit-observatory.workers.dev/s/http-428/mcp ↗
Description
Meaning of HTTP 428.
What our measurements say
HTTP 428 precondition-required is a remote MCP server published at agent-observatory-sensor.nolimit-observatory.workers.dev. It has been probed 6 times since 9/12/2026. It answered in 6 of them (100.0%), a near-uninterrupted record. Median response time is 36 ms, placing it among the faster endpoints. It exposes a broad tool surface of 30 tools. On the protocol side it still runs 2025-11-25 and has not moved to the newer spec.
Agent readability score
Can an LLM agent pick the right tool here — names, descriptions and parameter clarity are assessed.
Agent readability score
Agent readability score
Sign up free to generateEvent narrative
Sign up free to generateRaw observations
| Run | Era | Modern | ms | Legacy | ms | Versions |
|---|---|---|---|---|---|---|
| 2026-09-13 01:33:33 | Legacy | 404 | 35 | 200 | 32 | 2025-03-26 |
| 2026-09-12 23:31:36 | Legacy | 404 | 35 | 200 | 36 | 2025-03-26 |
| 2026-09-12 21:29:15 | Legacy | 404 | 36 | 200 | 36 | 2025-03-26 |
| 2026-09-12 19:27:29 | Legacy | 404 | 38 | 200 | 33 | 2025-03-26 |
| 2026-09-12 17:24:09 | Legacy | 404 | 44 | 200 | 37 | 2025-03-26 |
| 2026-09-12 15:21:42 | Legacy | 404 | 44 | 200 | 34 | 2025-03-26 |
Schema compliance
tools/list structure, inputSchema validity, and a functional smoke test — the components of the 0-100 score.
- tools/list schema valid
- inputSchema is valid JSON Schema
- Smoke test not run this round
- Cold-start: cold 34ms → warm 34ms (penalty 0ms)
Tools
Tools the server advertised in the latest measurement — measured, not catalog-claimed.
http-428Meaning of HTTP 428.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
utc-timeCurrent UTC timestamp.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
timezoneCurrent time in a named IANA timezone.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
validate-jsonCheck whether a body is valid JSON. The body is discarded.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
normalize-urlReturn origin, host, and path for a URL. Query and fragment are dropped.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
inspect-robotsFetch a public robots.txt and return group counts only.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
domain-shapeSplit a hostname into labels without WHOIS or ownership data.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
citationReturn host, scheme, and HTTP status for a URL. Page content is not stored.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
compatibilityShow how this request is classified. No identifiers are retained.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
status-catalogShort catalog of common HTTP status codes.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
iana-zonesCommon IANA timezone names for clock calls.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
web-fetchHTTP status and content type for a public URL. Body discarded.
zonestringjsonstringurlstringhoststringcitystringquerystringpathstringrefstringfeedstring
Availability history
Each block is one measurement round. Green: working response. Amber: responded but the server was returning errors (5xx). Red: no response at all.
Era history
Each cell is one probe run. Faded cells are incomplete probes — one leg did not answer, so the era is inconclusive.
Response time history
The two probe legs separately: modern server/discover and legacy initialize.
Event log
Derived by comparing consecutive probes — changes in era, protocol version, build and reachability.
- Added to watch — era: Legacy
Get your badge
Add this badge to your README — it updates automatically as measurements change.
[](https://mcpmetrics.io/servers/io-github-sadri-dridi-http-428)<a href="https://mcpmetrics.io/servers/io-github-sadri-dridi-http-428"><img src="https://mcpmetrics.io/badge/io.github.sadri-dridi/http-428/era.svg" alt="mcpmetrics"></a>You are seeing the last 7 days. Sign up for the full history. Which check failed and why is in the dashboard.
Sign up free to seeSimilar MCP servers
The catalog entries whose name and description are closest to this one, found with the same index the search box uses.
- HTTP 426 upgrade-requiredagent-observatory-sensor.nolimit-observatory.workers.dev
Meaning of HTTP 426.
- HTTP 412 precondition-failedagent-observatory-sensor.nolimit-observatory.workers.dev
Meaning of HTTP 412.
- HTTP 505 http-versionagent-observatory-sensor.nolimit-observatory.workers.dev
Meaning of HTTP 505.
- HTTP 404 not-foundagent-observatory-sensor.nolimit-observatory.workers.dev
Meaning of HTTP 404.
- HTTP 308 permanent-redirectagent-observatory-sensor.nolimit-observatory.workers.dev
Meaning of HTTP 308.
- HTTP 204 no-contentagent-observatory-sensor.nolimit-observatory.workers.dev
Meaning of HTTP 204.
Comments
Sign in to write a comment
No comments yet. Be the first.