javaperf

NPM · JAVAPERF · SCANNED AUG 3

Java profiling MCP via jcmd/jfr/jps. Diagnose performance, analyze threads, inspect JFR recordings.

Available components

+32 this week 77 77 Trust /100

Trust breakdown (6 categories)

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score →

Supply Chain Security86

No malware found by supply-chain analysis.Pass
Only part of the dependency tree could be resolved (94 of 98), so this covers what we could see, not the whole tree.Partial
No install/post-install scripts declared.Pass
Only part of the dependency tree could be resolved (94 of 98), so this covers what we could see, not the whole tree. View diagnostics → Partial

Provenance & Transparency97

Source repository is publicly reachable at the declared URL. View diagnostics → Pass
Cryptographically verified build provenance (signed, bound to theSharque/mcp-jperf). View diagnostics → Pass
Clear OSI-approved license (MIT).Pass
Actively maintained (last published 71 days ago).Pass
Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail

Schema Quality & AI Usability70

AI-judged instruction clarity (good).Pass
Tool/resource definitions use about 2587 tokens (~99/item across 26 items; 26 tools + 0 resources), lean.Pass
Usage-examples check failed: none of the tools include examples. See how to fix → Fail

Stability & Change Management23

Stability observed for 7 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial

Tool Coverage93

100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
78% of tool parameters carry a description.Partial

Capabilities100

Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass

Install

Add this component to your MCP client. Where a client-specific snippet is available, pick your client below and copy it straight into your config; otherwise use the connection detail shown.

npm · javaperf

Claude Codex opencode OpenClaw Hermes Other

# add to Claude Code

claude mcp add thesharque-javaperf -- npx -y javaperf

# add to Codex CLI

codex mcp add thesharque-javaperf -- npx -y javaperf

// opencode.json

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "thesharque-javaperf": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "javaperf"
      ],
      "enabled": true
    }
  }
}

# add to OpenClaw

openclaw mcp add thesharque-javaperf --command npx --arg -y --arg javaperf

# ~/.hermes/config.yaml

mcp_servers:
  thesharque-javaperf:
    command: "npx"
    args: ["-y", "javaperf"]

// mcp.json

{
  "mcpServers": {
    "thesharque-javaperf": {
      "command": "npx",
      "args": [
        "-y",
        "javaperf"
      ]
    }
  }
}

Changelog

Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.

3 Aug 26 +3
- Stability: unverified → 0.23 ▲ functional
2 Aug 26 +54
- Install scripts: unverified → pass ▲ security
- Provenance: unverified → pass ▲ security
- Known CVEs: unverified → partial ▲ security
- Malware scan: unverified → pass ▲ security
- Stability: Stability not yet verified: not enough scan history yet (needs a 30-day window). security
- The attested source repository moved: theSharque/mcp-jperf security
- Tool coverage: 100 → unverified ▼ functional
- License: unverified → pass ▲ functional
- Dependency health: unverified → partial ▲ functional
- Maintenance: unverified → pass ▲ functional
- MCP protocol: unverified → pass ▲ functional
- Schema quality: unverified → good ▲ functional
- Licence: MIT functional
31 Jul 26 +14
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
30 Jul 26 −18
- Malware scan: pass → unverified ▼ security
28 Jul 26 −21
- Tool coverage: 100 → unverified ▼ functional
- First check of Schema quality: unverified functional
27 Jul 26 45

First indexed and scored.

Show 3 earlier entries Hide earlier entries

Diagnostics

Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.

Captured 3 Aug 2026 · Analysed npm/[email protected]

Provenance verified

Ecosystem: npm · Outcome: verified

Reason: verified

Source repo:: theSharque/mcp-jperf
Certificate issuer:: https://token.actions.githubusercontent.com
Certificate SAN:: https://github.com/theSharque/mcp-jperf/.github/workflows/publish.yml@refs/heads/main
Rekor log index:: 1615698030
Predicate type:: https://slsa.dev/provenance/v1
Subject digest:: sha512:1b4f70aabe238b327abf6c18563878524e1f6ef87f7a089babcffebaf6f67e337f3623a28c401feda7b502539d9f6d2f6c9a693528f570e371c99c46e
Discovery method:: attestation_endpoint

Dependencies 94 packages

94 packages in the resolved dependency tree · 94 deprecated · 29 stale.

The dependency tree was only partially resolved, so these counts may be incomplete.

MCP tools — 26 exposed · ~2,587 tokens

The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability.

Tool Tokens

analyze_threads ~124

Thread dump (jstack -l). Default: plain text. Set structured=true for JSON lock-wait chains (live snapshot). Historical contention: profile_jfr_locks. Deadlock cycle: check_deadlock.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.
structured	boolean	—	Return structured JSON with lockWaitChains instead of plain-text dump. Default: false.
topN	integer	—	Maximum number of threads to include in the output. Default: 10. Increase for applications with many threads.

No output schema declared.

No examples provided.

check_deadlock ~78

Checks for Java-level deadlocks in the specified process. Parses jcmd Thread.print output and returns structured JSON: which threads are involved, what locks they hold/wait for, and the deadlock cycle. Use for automated analysis and reports.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.

No output schema declared.

No examples provided.

compiler_codecache ~30

jcmd Compiler.codecache — code heap usage and related JVM output.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	—

No output schema declared.

No examples provided.

compiler_queue ~27

jcmd Compiler.queue — methods queued for JIT compilation.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	—

No output schema declared.

No examples provided.

gc_class_stats ~56

jcmd GC.class_stats (class loader / metaspace style stats where supported—often JDK 21+). On older JDK returns error hint; use heap_info or heap_histogram instead.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	—

No output schema declared.

No examples provided.

gc_efficiency ~68

GC efficiency from .jfr: pause time vs freed bytes per collector/cause. Use after stop_profiling; complements profile_memory and heap_info. Not a general JFR summary (see parse_jfr_summary).

Input Output Examples

Name	Type	Req	Description
filepath	string	—	—
topN	integer	—	—

No output schema declared.

No examples provided.

gc_finalizer_info ~33

jcmd GC.finalizer_info — finalizer queue diagnostics for the live process.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	—

No output schema declared.

No examples provided.

heap_dump ~77

Creates .hprof for Eclipse MAT / VisualVM. After heap_live_histogram_diff picks a growing class, use MAT Path to GC Roots (exclude weak/soft). Saved to recordings/heap_dump.hprof. Warning: large file.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.

No output schema declared.

No examples provided.

heap_histogram ~94

Static class histogram (jcmd GC.class_histogram). For live growth over time use heap_live_histogram_diff instead.

Input Output Examples

Name	Type	Req	Description
all	boolean	—	Include unreachable objects. Triggers full GC and may cause application pause.
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.
topN	integer	—	Maximum number of top classes to return. Default: 20.

No output schema declared.

No examples provided.

heap_info ~47

Brief heap usage summary: capacities, used, committed regions. Quick snapshot without full dump.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.

No output schema declared.

No examples provided.

heap_live_histogram_diff ~145

Two GC.class_histogram snapshots spaced by intervalSeconds; returns classes whose instance count grew most. Use first in memory-leak workflow; then profile_memory and heap_dump (MAT path-to-GC-roots). Each snapshot walks the heap and may pause the app.

Input Output Examples

Name	Type	Req	Description
all	boolean	—	Include unreachable objects (-all). Triggers full GC and may pause the app.
intervalSeconds	integer	—	Seconds between baseline and snapshot histograms. Default: 5.
minInstanceDelta	integer	—	Ignore classes with instance growth below this threshold.
pid	integer	yes	Process ID from list_java_processes.
topN	integer	—	—

No output schema declared.

No examples provided.

list_java_processes ~96

Lists all running Java processes on the machine. Returns an array of objects with pid, mainClass, and args. Use this tool first to discover the target process PID before calling start_profiling or analyze_threads. Data is obtained via jps -l -m.

Input Output Examples

Name	Type	Req	Description
topN	integer	—	Maximum number of processes to return in the list. Default: 10. Use higher values if many Java processes are running.

No output schema declared.

No examples provided.

list_jfr_recordings ~78

Lists active and recent JFR recordings for a Java process (jcmd JFR.check). Returns recording id, duration, state (running/stopped), and filename. Use before stop_profiling to get the correct recordingId.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.

No output schema declared.

No examples provided.

native_memory_summary ~45

jcmd VM.native_memory summary=true. Requires JVM started with -XX:NativeMemoryTracking=summary or detail; otherwise explains how to enable.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	—

No output schema declared.

No examples provided.

parse_jfr_summary ~172

Parses a .jfr file and returns a structured summary: top methods by CPU samples, GC statistics, thread allocation stats, and anomaly hints (e.g. high GC count). Use for a quick high-level overview of the recording before diving into specific profiles.

Input Output Examples

Name	Type	Req	Description
events	array	—	Optional list of JFR event types to include. Default: jdk.ExecutionSample, jdk.GarbageCollection, jdk.JavaThreadStatistics, jdk.ThreadAllocationStatistics.
filepath	string	—	Path to .jfr file. Shortcuts: 'new_profile' (current, default) or 'old_profile' (previous). Or full path e.g. recordings/new_profile.jfr.
topN	integer	—	Maximum number of top methods to include in the summary. Default: 10.

No output schema declared.

No examples provided.

profile_frequency ~141

Call frequency profile from a .jfr file. Counts methods that appear at the leaf (top) of the stack in ExecutionSample events — i.e. methods that were actively executing when sampled. Returns the most frequently sampled methods (exclusive, not cumulative). Use when looking for hot spots or the most often executed code paths.

Input Output Examples

Name	Type	Req	Description
filepath	string	—	Path to .jfr file. Shortcuts: 'new_profile' (current, default) or 'old_profile' (previous). Or full path e.g. recordings/new_profile.jfr.
topN	integer	—	Maximum number of top methods by call frequency to return. Default: 10.

No output schema declared.

No examples provided.

profile_jfr_file_io ~93

Summarize file read/write events (jdk.FileRead, jdk.FileWrite): counts, bytes, top paths, stack hotspots. Events must exist in recording; configure via start_profiling preset or settingsFile (.jfc).

Input Output Examples

Name	Type	Req	Description
filepath	string	—	Path to .jfr. Shortcuts: new_profile, old_profile.
topN	integer	—	Top N paths/methods.

No output schema declared.

No examples provided.

profile_jfr_locks ~74

Lock contention from JFR: synchronized monitors (JavaMonitorBlocked) and j.u.c parking (ThreadPark). Live wait chains: analyze_threads structured=true. Deadlocks: check_deadlock. Enable events via custom .jfc if missing.

Input Output Examples

Name	Type	Req	Description
filepath	string	—	—
topN	integer	—	—

No output schema declared.

No examples provided.

profile_jfr_native ~51

CPU-style cumulative hotspots from jdk.NativeMethodSample stacks. Recording must enable NativeMethodSample (often requires custom .jfc).

Input Output Examples

Name	Type	Req	Description
filepath	string	—	—
topN	integer	—	—

No output schema declared.

No examples provided.

profile_jfr_network ~124

Summarize JDK socket I/O from a .jfr (jdk.SocketRead, jdk.SocketWrite): event counts, total bytes read/written where available, top endpoints (host:port / address), and cumulative stack hotspots. Recording must include those events (custom .jfc or preset that enables them). If emptyEvents, use start_profiling settingsFile.

Input Output Examples

Name	Type	Req	Description
filepath	string	—	Path to .jfr. Shortcuts: new_profile, old_profile, or absolute path.
topN	integer	—	Top N endpoints and methods.

No output schema declared.

No examples provided.

profile_memory ~142

JFR memory profile: top allocators by bytes/count, allocation stacks, OldObjectSample by class (allocation site, not GC roots). Pair with heap_live_histogram_diff, gc_efficiency, heap_dump+MAT. Requires profile preset recording.

Input Output Examples

Name	Type	Req	Description
filepath	string	—	Path to .jfr file. Shortcuts: 'new_profile' (current, default) or 'old_profile' (previous). Or full path e.g. recordings/new_profile.jfr.
sortBy	string	—	Primary ranking for topAllocators. Default: bytes.
topN	integer	—	Maximum number of top allocators to return. Default: 10.

No output schema declared.

No examples provided.

profile_time ~141

CPU time (bottleneck) profile from a .jfr file. Uses bottom-up aggregation: each method is counted in every sample where it appears in the stack, including time spent in callees. Returns methods consuming the most CPU time. Use when the goal is to find performance bottlenecks and slow code paths.

Input Output Examples

Name	Type	Req	Description
filepath	string	—	Path to .jfr file. Shortcuts: 'new_profile' (current, default) or 'old_profile' (previous). Or full path e.g. recordings/new_profile.jfr.
topN	integer	—	Maximum number of top methods by CPU time to return. Default: 10.

No output schema declared.

No examples provided.

start_profiling ~256

Starts JFR on the target PID. Rotates recordings (old_profile.jfr ← new_profile.jfr). Default preset is profile. Optional preset or settingsFile (.jfc, cwd-relative or absolute)—mutually exclusive. Builtin presets may omit socket/I/O/native/locks; use a custom .jfc for jdk.SocketRead/Write, FileRead/Write, JavaMonitorBlocked, jdk.ThreadPark, NativeMethodSample. Then list_jfr_recordings and stop_profiling.

Input Output Examples

Name	Type	Req	Description
duration	integer	yes	Recording duration in seconds. Typical: 10–60 quick, 300+ under load.
memorysize	string	—	JFR buffer size, e.g. 20M. Default JVM buffer applies if omitted.
pid	integer	yes	Process ID of the Java application. Use list_java_processes.
preset	string	—	Builtin settings name (e.g. profile, default). Effective default when omitted is profile. Mutually exclusive with settingsFile.
settingsFile	string	—	Path to .jfc file (cwd-relative or absolute). Mutually exclusive with preset.
stackdepth	integer	—	Stack depth for JFR events. Default 128.

No output schema declared.

No examples provided.

stop_profiling ~115

Stops an active JFR recording and saves it to recordings/new_profile.jfr. Use recordings/new_profile.jfr for current data, recordings/old_profile.jfr for previous (before/after comparison).

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java process that has the active recording. Must match the pid used in start_profiling.
recordingId	string	yes	ID of the recording to stop. This is the recordingId returned by start_profiling (e.g. '1' or '2').

No output schema declared.

No examples provided.

trace_method ~236

Builds a call tree for a specific method from a .jfr file. Filters ExecutionSample events to find stack traces containing the given class and method, then aggregates call paths. Use when you want to see who calls a particular method and from where. Limitation: JFR sampling (~10 ms) may miss very fast methods.

Input Output Examples

Name	Type	Req	Description
className	string	yes	Fully qualified class name (e.g. com.example.MyService) or a substring to match. Used to filter stack frames.
events	array	—	Optional list of JFR event types to parse. Default: jdk.ExecutionSample. Advanced users can specify other event types.
filepath	string	—	Path to .jfr file. Shortcuts: 'new_profile' (current, default) or 'old_profile' (previous). Or full path e.g. recordings/new_profile.jfr.
methodName	string	yes	Method name to search for (e.g. processRequest). Matches the method in the stack trace.
topN	integer	—	Maximum number of call paths (branches) to return in the call tree. Default: 10.

No output schema declared.

No examples provided.

vm_info ~44

JVM information: uptime, version, and flags. Useful for environment verification.

Input Output Examples

Name	Type	Req	Description
pid	integer	yes	Process ID of the Java application. Get this from list_java_processes.

No output schema declared.

No examples provided.

On this page

Handy links

Scoring key

80+ high trust
60–79 medium
below 60 low

How we score

Score history · last 30 days

27 Jul 3 Aug