NPMScan

Check an npm package for maintainer/ownership red flags

check_maintainer_changes

Read-only

Reconstructs a package's maintainer-change history straight from the npm packument — every published version carries the maintainers-list SNAPSHOT as it stood at that publish plus who actually ran npm publish (_npmUser), so diffing consecutive snapshots in publish-time order recovers exactly who was added or removed and when, with no extra API calls. Flags: (1) a maintainer added recently who then published a release shortly afterward on a package with real prior history — the account-takeover/hostile-handoff shape behind incidents like ua-parser-js, event-stream, and the 2025 chalk/debug ('qix') compromise; (2) a full, sudden replacement of the entire maintainer list; (3) a long-standing maintainer quietly dropped from the list; (4) a maintainer-list change that happened on npm's site AFTER the latest release — not yet tied to any published version, which is the more urgent case since it means access changed hands but nothing has shipped with it yet. Also cross-checks the declared GitHub repository: whether it still resolves to the same owner/name (a transfer/rename), whether it's reachable at all, and whether the latest npm release landed long after any real push activity there — repository.ownerLogin/ownerAvatarUrl name and show the CURRENT owning account (the new one after a transfer, not the one originally declared in package.json), with ownerAvatarUrl a proxied GitHub avatar image, both null whenever the repo check itself didn't reach GitHub. Use get_package/check_package_provenance first for the package's general health and publish-integrity signals; use this specifically for the 'who controls this package, and did that change recently' question. If this flags a newly added or fully turned-over maintainer, follow up with check_maintainer_blast_radius on that maintainer's username — it lists every other package the same account currently touches and flags a tight publish-time cluster across them, the 'did this compromise hit just one package or a dozen' question this tool can't answer on its own.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`name`	Yes	Exact npm package name, e.g. "lodash" or "@scope/name"

Output Schema

TableJSON Schema

Name	Required	Description	Default
`name`	Yes
`history`	Yes
`findings`	Yes
`riskTier`	Yes
`npmscanUrl`	Yes
`repository`	Yes
`totalScore`	Yes
`lookbackDays`	Yes
`currentMaintainers`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedSep 5, 2026

addedOutput schema / properties / repository / properties / ownerAvatarUrl
```
Added value: +{
+  "type": [
+    "string",
+    "null"
+  ]
+}
```
addedOutput schema / properties / repository / properties / ownerLogin
```
Added value: +{
+  "type": [
+    "string",
+    "null"
+  ]
+}
```

changedOutput schema / properties / repository / required

Previous value: -[
-  "checked",
-  "declaredRepository",
-  "currentFullName",
-  "transferred",
-  "archived",
-  "reachable",
-  "note"
-]New value: +[
+  "checked",
+  "declaredRepository",
+  "currentFullName",
+  "transferred",
+  "archived",
+  "reachable",
+  "ownerLogin",
+  "ownerAvatarUrl",
+  "note"
+]

AddedSep 1, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnly/openWorld/non-destructive, and the description still adds substantial behavior: results are derived from packument snapshots with 'no extra API calls', it enumerates four distinct flag categories, explains the GitHub repo cross-check, and documents null semantics for ownerLogin/ownerAvatarUrl when GitHub wasn't reached. This is far beyond what annotations convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

It is long, but dense with distinct information: mechanism, four flag types, repo cross-check, usage routing, and follow-up. Front-loaded with the core action. The single run-on paragraph makes it harder to scan than it needs to be, and a phrase or two could be trimmed.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex analysis tool with an output schema already present, the description covers the mechanism, every flag class, the secondary GitHub check, and how it relates to the two neighboring tools. Nothing an agent needs to decide or call correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter, and schema coverage is 100% with a clear example ('lodash' or '@scope/name'). The description adds no further naming or format guidance beyond the schema, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Names a specific verb and resource ('reconstructs a package's maintainer-change history straight from the npm packument') and immediately distinguishes itself from siblings by scoping to maintainer/ownership change rather than general health or publish integrity. An agent can tell exactly which question this tool answers.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes: use get_package/check_package_provenance for general health first, use this for 'who controls this package, and did that change recently', and follow up with check_maintainer_blast_radius for the cross-package blast-radius question. It even states the limitation ('the question this tool can't answer on its own'), which is unusually strong guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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