Rarefaction
NPM · RAREFACTION-LSP-MCP
LSP call graph for coding agents: a symbol's callers, callees, tests and live files in one call.
Available components
Last scanned (5 hours ago)
Scores higher than 93% of npm servers
Category Code Search and Documentation
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 → Why this is hard to score →
Supply Chain Security100
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- No install/post-install scripts declared.Pass
- 1 of 11 dependencies flagged as unhealthy. View diagnostics → Partial
Provenance & Transparency97
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Cryptographically verified build provenance (signed, bound to ip2k/rarefaction). View diagnostics → Pass
- Clear OSI-approved license (GPL-3.0-or-later).Pass
- Actively maintained (last published 15 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability66
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 730 tokens (~243/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management70
- Stability observed for 21 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 3 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
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.
- 4 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 63 to 67. That category is still filling its 30-day observation window: 19 days of observed history at the previous scan, 20 at this one. The score rises as the window fills, whether or not the server changes.
- 3 Nov 26 0
- Package version: 0.2.1 → 0.4.2 functional
- 2 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.
- 31 Oct 26 +1
- Package version: 0.2.1 → 0.4.2 functional
- 29 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.
- 27 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.
- 25 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 30 to 33. That category is still filling its 30-day observation window: 9 days of observed history at the previous scan, 10 at this one. The score rises as the window fills, whether or not the server changes.
- 22 Oct 26 +16
- Malware scan: unverified → pass ▲ security
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 5 Nov 2026 · Analysed npm/rarefaction-lsp-mcp@0.4.2
Provenance Verified
A signed build attestation was found and verified, binding this exact artifact to the source repository it claims to come from.
| Result | Verified |
|---|---|
| Ecosystem | npm |
| Reason | Verified |
| Discovered via | Registry attestation endpoint |
| Source repo | ip2k/rarefaction |
| Certificate issuer | https://token.actions.githubusercontent.com |
| Certificate SAN | https://github.com/ip2k/rarefaction/.github/workflows/release.yml@refs/tags/v0.4.2 |
| Rekor log index | 3347234128 |
| Predicate type | SLSA build provenance https://slsa.dev/provenance/v1 |
| Subject digest | sha512:268f9983347f0a4989842044bcf53ad11024a60322ca5d2e1d7cb086edcd3e2f3b52e30b101b2403a03ff8188d78393d9c678839bceaf6246b4a055e5 |
Background: How many MCP packages publish verified provenance →
Dependencies 11 packages
| Packages resolved | 11 |
|---|---|
| Stale | 1 |
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
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. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
orient Orient on a symbol ~319
Compact source context from language-server indexes: signature, body, callers, callees, tests, implementations and relevant files. Use before broad file reads in Swift, Rust, C/C++, TypeScript/JavaScript, Python and WebAssembly WAT projects. In mixed workspaces specify profile or use path:line:column. No cross-language/FFI edges are inferred. Increase up/down only when needed.
| Name | Type | Req | Description |
|---|---|---|---|
| down | integer | – | How many levels of callees to walk (default 1). |
| include_body | boolean | – | Include the symbol's source body. |
| max_body_lines | integer | – | Truncate the body after this many lines. |
| max_nodes | integer | – | Maximum graph nodes per direction and reference contexts; lower it for compact answers. |
| profile | string | – | Source-language profile; required for bare names in mixed workspaces. |
| project | string | – | Workspace-relative project directory, e.g. tools/driver for a nested Cargo package. Without it, a path:line:column symbol is answered from its enclosing Cargo workspace, else from its nearest project… |
| symbol | string | yes | A function, method, type or property: "updateLocation", "Engine.updateLocation", or an exact position "Sources/Engine.swift:204:10" (1-based line:column, on the name). |
| up | integer | – | How many levels of callers to walk (default 2: test cases usually sit one helper above the code they exercise). |
| Name | Type | Req | Description |
|---|---|---|---|
| body | object | – | – |
| callees | array | yes | – |
| callers | array | yes | – |
| external_callees_omitted | integer | yes | SDK / package callees dropped from `callees`. |
| freshness | object | yes | – |
| implementations | array | yes | – |
| live_files | array | yes | Files that can affect or be affected by the symbol within the walked depth. |
| profile | string | – | – |
| project_source_files | integer | yes | – |
| reference_contexts | array | – | – |
| references | array | – | For non-callables or servers without hierarchy: references grouped by file. |
| root | string | – | – |
| stats | object | yes | – |
| symbol | object | yes | – |
| test_run_hint | object | – | – |
| tests | array | yes | – |
| truncated | boolean | yes | – |
| type_hierarchy | object | – | – |
| warnings | array | – | – |
No examples provided.
scope Working set for a change ~285
The files a change to one symbol is likely to touch: orient's call-graph files (callers, callees, implementations, tests) plus files that have historically changed in the same commits as the symbol's file, each with its reason. Use when planning an edit, to know which files to read and check. Advisory, not a boundary: real changes often touch files outside it.
| Name | Type | Req | Description |
|---|---|---|---|
| down | integer | – | How many levels of callees to walk (default 1). |
| max_nodes | integer | – | Maximum graph nodes per direction and reference contexts; lower it for compact answers. |
| profile | string | – | Source-language profile; required for bare names in mixed workspaces. |
| project | string | – | Workspace-relative project directory, e.g. tools/driver for a nested Cargo package. Without it, a path:line:column symbol is answered from its enclosing Cargo workspace, else from its nearest project… |
| symbol | string | yes | A function, method, type or property: "updateLocation", "Engine.updateLocation", or an exact position "Sources/Engine.swift:204:10" (1-based line:column, on the name). |
| up | integer | – | How many levels of callers to walk (default 2: test cases usually sit one helper above the code they exercise). |
| Name | Type | Req | Description |
|---|---|---|---|
| co_change | object | yes | – |
| counts | object | yes | – |
| files | array | yes | The working set: symbol file first, then call-graph files, then files found only through history or links. |
| profile | string | yes | – |
| root | string | yes | – |
| stats | object | yes | – |
| symbol | object | yes | – |
| truncated | boolean | yes | The call-graph walk hit max_nodes. |
| warnings | array | yes | – |
No examples provided.
status Project, language server and index status ~126
Check detected source-language profiles, project roots, executables, compile flags and freshness. Call once before orient in a new project or when orientation is incomplete. Pass profile/project to inspect a nested package.
| Name | Type | Req | Description |
|---|---|---|---|
| profile | string | – | Source-language profile; required for bare names in mixed workspaces. |
| project | string | – | Workspace-relative project directory, e.g. tools/driver for a nested Cargo package. Without it, a path:line:column symbol is answered from its enclosing Cargo workspace, else from its nearest project… |
| Name | Type | Req | Description |
|---|---|---|---|
| profiles | array | yes | – |
| root | string | yes | – |
No examples provided.
How do I install the Rarefaction MCP server?
Rarefaction runs locally as an npm package, launched with npx -y rarefaction-lsp-mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
npm · rarefaction-lsp-mcp
claude mcp add ip2k-rarefaction-lsp-mcp -- npx -y rarefaction-lsp-mcp
What is the Rarefaction MCP server?
Rarefaction is an MCP server listed in the public MCP registry as io.github.ip2k/rarefaction-lsp-mcp. LSP call graph for coding agents: a symbol's callers, callees, tests and live files in one call. This page covers its npm package (rarefaction-lsp-mcp).
Is the Rarefaction MCP server safe to use?
Rarefaction scores 89 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 5 November 2026. It declares no install or post-install scripts. Its build provenance is signed and verified. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Rarefaction MCP server expose?
Rarefaction exposes 3 tools: orient, scope, status. Their descriptions and schemas cost roughly 730 tokens of context every time the server is loaded.
Is the Rarefaction MCP server still maintained?
Rarefaction is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the Rarefaction MCP server under?
Rarefaction declares the GPL-3.0-or-later licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.