| name | group-packages-for-research |
| description | Use when a command needs to partition a `ScanResult.updates[]` array (from `experiments:scan-npm-updates`) into deterministic, bounded subagent groups before dispatching parallel research โ for example `/experiments:npm-update-deep-patch` (and future deep-* siblings) before invoking `parallel-research-workflow`. Trigger phrases include "group these updates", "partition this scan result", or any flow handing a `ScanResult` to a fan-out workflow. Pure: same input โ same output, no network, no filesystem reads. Returns `{ groups: [{ groupId, bucketKey, packages }], warnings }` JSON. |
group-packages-for-research
Partition a list of ScanResult.updates[] into deterministic, bounded groups suitable for one-subagent-per-group parallel research. The grouping is reproducible, monorepo-aware (via the @scope/ heuristic), and capped per group so any single subagent's context stays bounded.
This skill is the grouping primitive consumed by parallel-research-workflow (and therefore by /experiments:npm-update-deep-patch). It is pure: same input โ same output, no network, no filesystem reads.
Inputs
-
updates (required): an array of update records conforming to the existing ScanResult.updates[] shape produced by experiments:scan-npm-updates. Each record SHALL have at minimum name, currentVersion, targetVersion, location, and sourceFile.
-
maxPerGroup (optional, integer, default 8): override for the per-group cap. Inclusive valid range [1, 32]. A value outside this range aborts with:
Error: maxPerGroup must be between 1 and 32, got <value>.
The skill SHALL NOT mutate the input array.
Output contract
Emit a single JSON object โ raw, no Markdown fences, no surrounding prose:
{
groups: Array<{
groupId: string;
bucketKey: string;
packages: Array<{
name: string;
currentVersion: string;
targetVersion: string;
location: string;
sourceFile: string;
}>;
}>;
warnings: string[];
}
groups ordered by groupId ascending (locale-insensitive string compare).packages within each group preserve the post-sort order from the deterministic-ordering step below.warnings deduplicated (same string appearing twice โ keep one).
Empty input โ { "groups": [], "warnings": [] }.
Algorithm
Step 1 โ Validate maxPerGroup
If the caller provided maxPerGroup and it is not an integer in [1, 32], abort with the message above. Otherwise, the effective cap is MAX_PER_GROUP = maxPerGroup ?? 8.
Step 2 โ Deterministic sort
Sort the input by package name ascending using a stable, locale-insensitive comparison (e.g. Array.prototype.sort with (a, b) => a.name < b.name ? -1 : a.name > b.name ? 1 : 0). Scoped names sort by their full string including the leading @, so @tanstack/react-query precedes react.
The same input array SHALL always produce the same group partition and the same group ids โ no reliance on map/dict iteration order, no clock, no randomness.
Step 3 โ Bucketing
Walk the sorted list once and place each record into a bucket keyed by:
- For a scoped name
@scope/pkg โ bucket key = <scope> (lowercased).
- For an unscoped name
pkg โ bucket key = solo-<pkg> (lowercased, no other transformation at this stage).
All updates that share a scope coalesce into the same bucket. Unscoped updates are singletons by construction.
Step 4 โ Cap and chunk
For each bucket whose package count exceeds MAX_PER_GROUP, split it into chunks of size MAX_PER_GROUP preserving sort order. The final chunk contains the remainder. Buckets at or below the cap stay as a single chunk.
Step 5 โ Group id generation
For each chunk, compute the groupId as <sanitized-bucket-key>-<n> where:
n is 1-indexed within the bucket after splitting.- Sanitization of the bucket key: lowercase, replace any run matching
[^a-z0-9]+ with -, then trim leading and trailing -.
Examples:
| Bucket key | Sanitized | n=1 group id |
|---|
tanstack | tanstack | tanstack-1 |
radix-ui | radix-ui | radix-ui-1 |
solo-react-router | solo-react-router | solo-react-router-1 |
solo-vitest | solo-vitest | solo-vitest-1 |
If sanitization collapses two distinct bucket keys to the same id (rare; e.g., radix.ui and radix-ui), the second one SHALL receive a numeric suffix increment AND the skill SHALL append bucket key collision avoided via sanitization to warnings (deduplicated).
Step 6 โ Emit JSON
Build the output with groups sorted by groupId ascending, packages within each group preserving the Step-2 sort order, warnings deduplicated. Print the raw JSON object as the only output.
Out-of-scope behaviors
The skill SHALL NOT:
- Make any network call (
npm view, gh api, fetch, etc.).
- Read changelogs, package size, dependency graphs, or
repository.directory metadata.
- Read or write any file on disk.
- Vary its output based on environment, locale, or wall-clock time.
Grouping decisions rely solely on the input array. This guarantees that the same input on two different machines with different network conditions produces byte-identical output.
Worked example
Input (passed by /experiments:npm-update-deep-patch after a scan):
[
{
"name": "@tanstack/react-query",
"currentVersion": "^5.90.18",
"targetVersion": "^5.90.20",
"location": "workspace:@m0n0lab/wealth-react",
"sourceFile": "apps/wealth-react/package.json"
},
{
"name": "@tanstack/react-table",
"currentVersion": "^8.20.0",
"targetVersion": "^8.20.5",
"location": "workspace:@m0n0lab/wealth-react",
"sourceFile": "apps/wealth-react/package.json"
},
{
"name": "vitest",
"currentVersion": "4.0.18",
"targetVersion": "4.0.24",
"location": "catalog:default",
"sourceFile": "pnpm-workspace.yaml"
},
{
"name": "react",
"currentVersion": "^19.0.0",
"targetVersion": "^19.0.14",
"location": "workspace:@m0n0lab/wealth-react",
"sourceFile": "apps/wealth-react/package.json"
}
]
After Step 2 (deterministic sort):
@tanstack/react-query, @tanstack/react-table, react, vitest
After Step 3 (bucketing):
tanstack โ [@tanstack/react-query, @tanstack/react-table]
solo-react โ [react]
solo-vitest โ [vitest]
After Step 4 (cap): no bucket exceeds 8, no chunking.
After Step 5 (group ids):
tanstack-1solo-react-1solo-vitest-1
Output:
{
"groups": [
{
"groupId": "solo-react-1",
"bucketKey": "solo-react",
"packages": [
{
"name": "react",
"currentVersion": "^19.0.0",
"targetVersion": "^19.0.14",
"location": "workspace:@m0n0lab/wealth-react",
"sourceFile": "apps/wealth-react/package.json"
}
]
},
{
"groupId": "solo-vitest-1",
"bucketKey": "solo-vitest",
"packages": [
{
"name": "vitest",
"currentVersion": "4.0.18",
"targetVersion": "4.0.24",
"location": "catalog:default",
"sourceFile": "pnpm-workspace.yaml"
}
]
},
{
"groupId": "tanstack-1",
"bucketKey": "tanstack",
"packages": [
{
"name": "@tanstack/react-query",
"currentVersion": "^5.90.18",
"targetVersion": "^5.90.20",
"location": "workspace:@m0n0lab/wealth-react",
"sourceFile": "apps/wealth-react/package.json"
},
{
"name": "@tanstack/react-table",
"currentVersion": "^8.20.0",
"targetVersion": "^8.20.5",
"location": "workspace:@m0n0lab/wealth-react",
"sourceFile": "apps/wealth-react/package.json"
}
]
}
],
"warnings": []
}
Note that the output groups array is sorted ascending by groupId (solo-react-1, solo-vitest-1, tanstack-1), independent of the order the buckets were filled in.
See also
parallel-research-workflow โ the consumer of this skill's output. Dispatches one subagent per group./experiments:npm-update-deep-patch โ the first command in the deep-update family that wires scan-npm-updates โ this skill โ parallel-research-workflow.experiments:scan-npm-updates โ produces the ScanResult.updates[] consumed here.
