pensketch
NPM · @PENSKETCH/MCP · SCANNED SEP 23
An MCP server for pensketch: check, render and rasterise hand-sketched diagrams.
Available components
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
- 0 of 8 dependencies flagged as unhealthy. View diagnostics → Pass
Provenance & Transparency71
- Repository check failed: no source repository is declared. See how to fix → View diagnostics → Fail
- Cryptographically verified build provenance (signed, bound to alpha-nu/pensketch). View diagnostics → Pass
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 7 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability77
- 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 3762 tokens (~313/item across 12 items; 4 tools + 8 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 Management53
- Stability observed for 16 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage99
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 96% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
How do I install the pensketch MCP server?
pensketch runs locally as an npm package, launched with npx -y @pensketch/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 · @pensketch/mcp
claude mcp add alpha-nu-pensketch -- npx -y @pensketch/mcp
{
"mcpServers": {
"alpha-nu-pensketch": {
"command": "npx",
"args": [
"-y",
"@pensketch/mcp"
]
}
}
} {
"servers": {
"alpha-nu-pensketch": {
"command": "npx",
"args": [
"-y",
"@pensketch/mcp"
]
}
}
} codex mcp add alpha-nu-pensketch -- npx -y @pensketch/mcp
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"alpha-nu-pensketch": {
"type": "local",
"command": [
"npx",
"-y",
"@pensketch/mcp"
],
"enabled": true
}
}
} openclaw mcp add alpha-nu-pensketch --command npx --arg -y --arg @pensketch/mcp
mcp_servers:
alpha-nu-pensketch:
command: "npx"
args: ["-y", "@pensketch/mcp"] {
"McpServers": {
"alpha-nu-pensketch": {
"Transport": "stdio",
"Command": "npx",
"Arguments": [
"-y",
"@pensketch/mcp"
]
}
}
} assistant mcp add alpha-nu-pensketch -t stdio -c npx -a -y @pensketch/mcp
{
"mcpServers": {
"alpha-nu-pensketch": {
"command": "npx",
"args": [
"-y",
"@pensketch/mcp"
]
}
}
} 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.
- 21 Sept 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.
- 19 Sept 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.
- 17 Sept 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.
- 16 Sept 26 +15
- Malware scan: unverified → pass ▲ security
- 15 Sept 26 −14
- Malware scan: pass → unverified ▼ security
- Schema quality: 256 → 313 ▼ functional
- Package version: 0.10.0 → 0.13.0 functional
- Package version: 0.10.0 → 0.12.0 functional
- 13 Sept 26 +27
- Malware scan: unverified → pass ▲ security
- Known CVEs: unverified → pass ▲ security
- Dependency health: unverified → 1.00 ▲ functional
- 12 Sept 26 −24
- Known CVEs: pass → unverified ▼ security
- Malware scan: pass → unverified ▼ security
- Tool safety: pass → unverified ▼ security
- Stability: Stability not yet verified: we do not have a sandbox capture of the MCP schema this version of the package serves yet. security
- Schema quality: 2567 → 3079 ▼ functional
- Dependency health: 1.00 → unverified ▼ functional
- Capabilities: pass → unverified ▼ functional
- Tool coverage: 100 → unverified ▼ functional
- Schema quality: 100 → unverified ▼ functional
- Stability: unverified → 0.17 ▲ functional
- Package version: 0.8.0 → 0.10.0 functional
- Package version: 0.8.0 → 0.9.0 functional
- 7 Sept 26 76
First indexed and scored.
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 23 Sept 2026 · Analysed npm/@pensketch/mcp@0.13.0
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 | alpha-nu/pensketch |
| Certificate issuer | https://token.actions.githubusercontent.com |
| Certificate SAN | https://github.com/alpha-nu/pensketch/.github/workflows/publish.yml@refs/heads/main |
| Rekor log index | 2845011656 |
| Predicate type | https://slsa.dev/provenance/v1 |
| Subject digest | sha512:848fdf65f742e982d3a0e502d35f3454e9a4357dc4c46526a96f7265a60aa830a420b682a5406479ca2643385a9a22391c6750fffaca76367d9d790b8 |
Background: How many MCP packages publish verified provenance →
Dependencies 8 packages
| Packages resolved | 8 |
|---|---|
| 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 →
check_diagram Check a diagram for layout defects ~999
Reports what neither the types nor the schema can see: overlapping boxes, a label a connector will be drawn through, text too wide for its box, a node half out of its lane, a node no edge names, a depth the renderer would refuse. Draws nothing. Every coordinate is yours: pensketch performs no layout and routes no edges. Text is never measured, so a box does not grow to fit its label. It takes extrude and depth, where it refuses hops: hops change no finding - though where a hop breaks the very line a `label-collision` names, the finding stands and the sentence naming that edge does not - and depth changes the geometry every finding measures - an extruded node is measured over the box its slab sweeps, so a slab that crosses the frame or its neighbour is reported here rather than seen in the picture. Pass the pair you will render with, or the findings are for a drawing you are not making. Pass `anchors: true` and the report ends with the numeric points every edge end resolved to - the arithmetic for verifying a layout you cannot look at. `render_diagram` reports these same findings for the drawing it just made, so reach for this one when you want findings without markup, or before spending a `render_png` - stdio transport only; over HTTP there is no raster - on a diagram you have not checked.
| Name | Type | Req | Description |
|---|---|---|---|
| anchors | boolean | – | Append the resolved end points of every edge to the report, one line each: the two points its drawn line actually begins and ends at - a side fraction walked, an extruded anchor carried onto the silh… |
| depth | number | – | How deep a slab is drawn, in px, for every node without a `depth` of its own. Default 12, calibrated on a box; a pill wants about a third of its height, and a diamond reads as a folded corner at ever… |
| diagram | object | yes | A diagram: nodes, edges, braces and notes as plain data. Read the pensketch://schema resource - or call the get_schema tool, the same document - for every field. The whole diagram is validated agains… |
| extrude | boolean | – | Draw every node as a slab: its outline redrawn offset up and to the right and joined to it. A node's own `extrude` wins over this either way, so an extruded diagram can flatten one node and a flat on… |
| viewBox | array | – | [minX, minY, width, height], the four numbers the <svg> carries. Without it the out-of-bounds rule cannot run and does not. |
No output schema declared.
No examples provided.
get_schema The JSON Schema for a diagram ~110
Returns the JSON Schema for the diagram the drawing tools take: every field of a node, an edge, a brace and a note, with what each means. The same document as the pensketch://schema resource, as a tool, for clients that cannot read resources. Call it once per session at most - it changes only when the server version does; this build is @pensketch/mcp 0.13.0. Every mismatch is also reported field by field when a diagram is refused.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
render_diagram Render a diagram to SVG ~1,311
Returns SVG markup for a diagram, and beside it the layout findings for the drawing it just made: overlapping boxes, text too wide for its box, a node out of frame. Two content blocks: the markup alone, then the findings - when saving to a file, write the first block only, because anything appended after </svg> makes the file invalid. Deterministic: the same diagram and seed produce the same bytes. Every coordinate is yours: pensketch performs no layout and routes no edges. Text is never measured, so a box does not grow to fit its label. The markup names the handwriting font stack, so a browser draws it in the reader's own hand-drawn face. It is returned, not displayed: many clients render none of it, so save it to a file, embed it in a page, or hand it onward rather than assuming the reader has seen the picture.
| Name | Type | Req | Description |
|---|---|---|---|
| animate | boolean | – | Return an <svg> that draws itself, stroke by stroke, in the order a hand would have drawn it: each region first, each shape with its own label, then the connectors, then the annotations. It carries i… |
| depth | number | – | How deep a slab is drawn, in px, for every node without a `depth` of its own. Default 12, calibrated on a box; a pill wants about a third of its height, and a diamond reads as a folded corner at ever… |
| diagram | object | yes | A diagram: nodes, edges, braces and notes as plain data. Read the pensketch://schema resource - or call the get_schema tool, the same document - for every field. The whole diagram is validated agains… |
| duration | number | – | How long the whole drawing takes, first stroke to last, in ms. Requires animate. Default: scaled to the drawing at 70 ms per stroke, clamped to [2000, 6000] - a six-stroke sketch and a six-hundred-st… |
| easing | string | – | The CSS easing every stroke takes, as an <easing-function>. Requires animate. Default ease-out. |
| extrude | boolean | – | Draw every node as a slab: its outline redrawn offset up and to the right and joined to it. A node's own `extrude` wins over this either way, so an extruded diagram can flatten one node and a flat on… |
| hops | boolean | – | Draw every connector as going over the ones it crosses, breaking the line underneath where they meet. An edge's own `hop` wins over this either way. Default false. |
| label | string | – | An accessible name, set as aria-label on the <svg>. |
| seed | integer | – | Picks which drawing of the same data you get. Default 1. |
| sequence | string | – | Which order the drawing draws itself in. 'hand', the default, is the order a hand would lay the picture down: each region, each shape with its label, then the connectors, then the annotations. 'flow'… |
| stroke | number | – | How long the longest single stroke takes to draw, in ms; shorter strokes take proportionally less, floored at a tenth of this. Requires animate. Default 500. |
| viewBox | array | yes | [minX, minY, width, height], the four numbers the <svg> carries. |
No output schema declared.
No examples provided.
render_png Render a diagram to a PNG you can look at ~756
Rasterizes a diagram so it can be displayed. The PNG draws text in a stand-in font, not the handwriting stack the SVG names, so it is authoritative about structure and not about fit; use check_diagram for fit. Every coordinate is yours: pensketch performs no layout and routes no edges. Scale is capped at 4, and an oversized request is refused rather than served.
| Name | Type | Req | Description |
|---|---|---|---|
| depth | number | – | How deep a slab is drawn, in px, for every node without a `depth` of its own. Default 12, calibrated on a box; a pill wants about a third of its height, and a diamond reads as a folded corner at ever… |
| diagram | object | yes | A diagram: nodes, edges, braces and notes as plain data. Read the pensketch://schema resource - or call the get_schema tool, the same document - for every field. The whole diagram is validated agains… |
| extrude | boolean | – | Draw every node as a slab: its outline redrawn offset up and to the right and joined to it. A node's own `extrude` wins over this either way, so an extruded diagram can flatten one node and a flat on… |
| hops | boolean | – | Draw every connector as going over the ones it crosses, breaking the line underneath where they meet. An edge's own `hop` wins over this either way. Default false. |
| scale | number | – | 1 to 4. Default 2, for a legible image. |
| seed | integer | – | – |
| viewBox | array | yes | [minX, minY, width, height], the four numbers the <svg> carries. |
No output schema declared.
No examples provided.
What is the pensketch MCP server?
pensketch is an MCP server listed in the public MCP registry as io.github.alpha-nu/pensketch. An MCP server for pensketch: check, render and rasterise hand-sketched diagrams. This page covers its npm package (@pensketch/mcp).
Is the pensketch MCP server safe to use?
pensketch scores 83 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 23 September 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 pensketch MCP server expose?
pensketch exposes 4 tools: check_diagram, render_diagram, get_schema, render_png. Their descriptions and schemas cost roughly 3,176 tokens of context every time the server is loaded.
Is the pensketch MCP server still maintained?
pensketch is still listed as active in the MCP registry. We last reached this channel on 23 September 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 pensketch MCP server under?
pensketch declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.