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io.github.cyanheads/first-epss-mcp-server

io.github.cyanheads/first-epss-mcp-servercyanheadsstreamable-httpv0.1.3Scanned

Look up FIRST EPSS scores and daily history, find CVEs by threshold, and prioritize them with CVSS.

5 tools: 1 change things and 4 only read.

Tools: 0 delete, 0 irreversible, 1 write, 4 read.
  • Reads private data · 0
  • Reads text others write · 4
  • Can send data out · 0
  • 1 finding

Anlyon alternative

1 of these tools change something. Run those as governed actions.

Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.

Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.

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Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

5 tools

Changes things 1Claude Code: ask
  • epss_prioritize_cvesAssign remediation tiers using latest or dated EPSS and caller-supplied CVSS base severity.Reads text others write1 finding

    Why it is in this group

    • The description's first verb is "assign": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.

    Findings

    • Warn

      The server marks "epss_prioritize_cves" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "assign": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Assign remediation tiers using latest or dated EPSS and caller-supplied CVSS base severity. Defaults are severity >= 7 and EPSS probability >= 0.10; select percentile explicitly for population rank. Missing severity stays in epssOnly and missing EPSS stays unscored. Thresholds are policy conventions, not FIRST guidance. Process up to 500 unique entries from batchOffset, returning whole entries within the byte budget. Resume using nextBatchOffset as batchOffset, the original cves with original cvssBaseScore values, returned score date as date, and the same severityThreshold and likelihood. Deferred lists may be declared previews; withheldCves were already processed.

    Annotations the server declares

    • readOnlyHint: true
    • idempotentHint: true
    • openWorldHint: true
Only reads 4Show 4 read-only tools
  • epss_get_scoresRetrieve latest available or historically dated FIRST EPSS probability and percentile for supplied CVEs.Reads text others writeNo findings

    Why it is in this group

    • The name "epss_get_scores" says "get": a word for reading.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    Description, as the server wrote it
    Retrieve latest available or historically dated FIRST EPSS probability and percentile for supplied CVEs. Process up to 500 unique entries from batchOffset; response byte limits can return fewer whole entries. Resume with nextBatchOffset as batchOffset, the original cves and returned score date as date. deferredCves were not queried; withheldCves were processed but omitted, and either list can be a declared preview. Missing scores remain unknown; use epss_list_reference for coverage and interpretation.

    Annotations the server declares

    • readOnlyHint: true
    • idempotentHint: true
    • openWorldHint: true
  • epss_get_timeseriesRetrieve an EPSS anchor and up to 30 preceding daily observations for up to 50 unique CVEs from batchOffset.Reads text others writeNo findings

    Why it is in this group

    • The name "epss_get_timeseries" says "get": a word for reading.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    Description, as the server wrote it
    Retrieve an EPSS anchor and up to 30 preceding daily observations for up to 50 unique CVEs from batchOffset. Response byte limits retain whole history items. Resume CVE batches with nextBatchOffset as batchOffset, the original cves and returned score date as date; withheldCves were processed, deferredCves were not queried, and lists can be declared previews. Exact 7-day and 30-day deltas require their calendar baselines; gaps remain unknown. Model boundaries do not explain score movement. Re-anchor using previousAnchorDate for the preceding history window; that snapshot may be unavailable.

    Annotations the server declares

    • readOnlyHint: true
    • idempotentHint: true
    • openWorldHint: true
  • epss_list_referenceExplain FIRST EPSS interpretation, model publishing dates, lookup coverage and transparent prioritization policy.No findings

    Why it is in this group

    • The name "epss_list_reference" says "list": a word for reading.
    Description, as the server wrote it
    Explain FIRST EPSS interpretation, model publishing dates, lookup coverage and transparent prioritization policy. Use this static reference before interpreting missing scores, score movement or probability versus percentile thresholds.

    Annotations the server declares

    • readOnlyHint: true
    • idempotentHint: true
    • openWorldHint: false
  • epss_query_thresholdDiscover CVEs using inclusive EPSS or percentile bounds, CVE year or dataset-addition recency; filters intersect and at least one is required.Reads text others writeNo findings

    Why it is in this group

    • The name "epss_query_threshold" says "query": a word for reading.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    Description, as the server wrote it
    Discover CVEs using inclusive EPSS or percentile bounds, CVE year or dataset-addition recency; filters intersect and at least one is required. Examine one candidate page ordered by EPSS descending. Each serialized response surface fits 65536 UTF-8 bytes; budgetLimited and withheldCount disclose whole matches withheld, with nextOffset at the first withheld match. Year filtering can return an empty page with nextOffset; candidateTotal is a broad-query total, not an exact-year total. Continue with the same filters, limit, returned score date and nextOffset.

    Annotations the server declares

    • readOnlyHint: true
    • idempotentHint: true
    • openWorldHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged private-data or outbound.

Reads private data0
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write4
Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
Can send data out0
Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnepss_prioritize_cves

    The server marks "epss_prioritize_cves" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":true}; The description's first verb is "assign": a word for a change.

    What this check looks for

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 0.1.3. Values in angle brackets are yours to fill in.

claude mcp add --transport http first-epss https://first-epss.caseyjhand.com/mcp
claude mcp add --transport http first-epss https://first-epss.caseyjhand.com/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__first-epss__epss_get_scores",
      "mcp__first-epss__epss_get_timeseries",
      "mcp__first-epss__epss_query_threshold",
      "mcp__first-epss__epss_list_reference"
    ],
    "ask": [
      "mcp__first-epss__epss_prioritize_cves"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as first-epss. Review it before you use it.

Capability tags behind 4 rules
  • mcp__first-epss__epss_get_scores untrusted-input
  • mcp__first-epss__epss_get_timeseries untrusted-input
  • mcp__first-epss__epss_query_threshold untrusted-input
  • mcp__first-epss__epss_prioritize_cves untrusted-input

Pin

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/io.github.cyanheads/first-epss-mcp-server/verify?hash=fa6d11d2140b0fb9c817eebcf2defc31e3b8883510a289f50b6cccb3764d80a1" | jq -e '.changed == false'

Pinned hash fa6d11d2140b, from Oct 24, 2026, 21:17 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/io.github.cyanheads/first-epss-mcp-server/changes.xml

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Source: MCP Registry · repository. Synced Oct 24, 2026, 21:17 UTC.