Caption File Check
https://powmcp.com/caption-file-check/mcp ↗
Description
Parse WebVTT, SRT, or TTML for conformance, timing, overlaps, line length, and reading speed.
What our measurements say
Caption File Check is a remote MCP server published at powmcp.com. It has been probed 7 times since 9/12/2026. It answered in 7 of them (100.0%), a near-uninterrupted record. Median response time is 452 ms, placing it among the faster endpoints. It offers a narrow, focused set of 2 tools. On the protocol side it speaks the 2026-07-28 stateless spec.
Agent readability score
Can an LLM agent pick the right tool here — names, descriptions and parameter clarity are assessed.
Agent readability score
Strengths
- Tool names (caption_check, caption_compare) clearly indicate their distinct purposes.
- No overlap between tools; each serves a unique function (single-file check vs. comparison).
Weaknesses
- Parameter types like 'profile' are undefined (type: null), creating ambiguity.
- Descriptions lack explicit error handling details (e.g., invalid URLs, file size limits).
- Truncated text in descriptions (e.g., 'SSRF-gua') reduces clarity.
caption_check— Parameter 'profile' has undefined type (null) and no usage context.caption_compare— Parameter 'profile' similarly lacks type definition and purpose explanation.
Verdict
Event narrative
Risk: low
Advice
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 failed: —
- Cold-start: cold 111ms → warm 111ms (penalty 0ms)
Tools
Tools the server advertised in the latest measurement — measured, not catalog-claimed.
caption_checkPreflight one caption or subtitle file before delivery. Attach a WebVTT (.vtt), SRT (.srt), or TTML/IMSC (.ttml/.xml) caption file in chat or give a publicly fetchable URL and it downloads the artifact under an SSRF-guarded, 2 MB-capped fetch, detects the format by content and the byte encoding and BOM, then parses it with the real spec engine (the WebVTT spec parser, a dedicated SRT parser, or the imscJS TTML/IMSC profile engine) and returns deterministic evidence: pass/fail, cue count, structural spec and IMSC profile-conformance errors, overlapping / negative / out-of-order / empty cues, per-line length, and per-cue and summary reading speed (CPS) against a named platform profile (netflix-adult-20, netflix-children-17, youtube, ebu-tt). It reports only source-file conformance, timing, e
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caption_compareCompare exactly two caption or subtitle files under identical bounded checks: an original versus its translated track, before versus after a timing fix, or a format migration. Attach two WebVTT, SRT, or TTML/IMSC caption files in chat or give two publicly fetchable URLs and it runs the same SSRF-guarded, 2 MB-capped preflight as caption_check on each, then aligns them by cue index and reports side-by-side pass status, detected-format and encoding differences, the cue-count delta, timing drift and overlap differences, reading-speed (CPS) regressions, structural-error deltas, and a winner only when the measured checks separate the two. Use caption_check for a single file. It reports only source-file conformance, timing, encoding, and reading-speed facts against a dated profile: never transla
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Availability history
Event log
Derived by comparing consecutive probes — changes in era, protocol version, build and reachability.
- Added to watch — era: Dual-era
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[](https://mcpmetrics.io/servers/com-powmcp-caption-file-check)<a href="https://mcpmetrics.io/servers/com-powmcp-caption-file-check"><img src="https://mcpmetrics.io/badge/com.powmcp/caption-file-check/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.
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