Search the built-in library of structural whiteboard stencils — ready-made hand-drawn graphics: flowchart/UML/ER/BPMN symbols, scrum columns, org-chart nodes, gantt, lo-fi/UX wireframe widgets (buttons, forms, tables, alerts, navs), charts, device frames, stick figures. A stencil is a MINI-WHITEB...
Risk signalsAccepts freeform code/query input (query)
Part of the Stable Baseline server.
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AI agents call listWhiteboardStencils to retrieve information from Stable Baseline without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though listWhiteboardStencils only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"listWhiteboardStencils": {}
}
}See the full Stable Baseline policy for all 184 tools.
These attack patterns abuse exactly the kind of access listWhiteboardStencils gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Search the built-in library of structural whiteboard stencils — ready-made hand-drawn graphics: flowchart/UML/ER/BPMN symbols, scrum columns, org-chart nodes, gantt, lo-fi/UX wireframe widgets (buttons, forms, tables, alerts, navs), charts, device frames, stick figures. A stencil is a MINI-WHITEBOARD (a collection of elements), NOT a single shape. Each result returns: key, title (a real human name e.g. 'Alerts', not an index), kind ('symbol' | 'template'), labels (the TEXT it actually contains — its real content, e.g. an Alerts template's variant messages), size ({w,h} px), summary, pack, category; plus the full pack/category lists. The two kinds are used DIFFERENTLY: • SYMBOL = one atomic labelled node (flowchart Process/Decision, BPMN task, org node). Place + label + connect: addWhiteboardElements({type:'stencil', stencilKey, id:'n1', text:'Review', width, height}) — the text auto-fits its single slot and an arrow's start/end {id:'n1'} binds to it like any shape. A few symbols are text-less FRAMES (e.g. a UML class box = rectangle + divider line): place create-only, then use the placement result's children (shapes + x/y/w/h) and groupId to add type:'text' specs INTO the regions — pass that groupId so the text is one unit with the frame. • TEMPLATE = a multi-component layout (Alerts, Forms, Tables, Charts, device frames). Place the WHOLE thing: addWhiteboardElements({type:'stencil', stencilKey, x, y, width?, height?}); the placement RESULT returns stencils[].children (each child's id + text + colour + position x/y/w/h, so you can group children into rows/sections) so you then keep / retext / recolour / DELETE specific parts via updateWhiteboardScene (e.g. delete the info + error rows to keep only the green success alert). Do NOT pass a single text to a template — read its labels to see its parts, then edit them by id. To make several similar items, build one then duplicateWhiteboardElements({groupId, dx}) to stamp consistent copies (like copy-paste in the UI). SEARCH TIPS: prefer BROAD single words ('decision','alert','form','phone','process'); content words match the embedded labels too (searching 'success' finds the Alerts template). If nothing exact matches, results auto-broaden (broadened:true); pass pack/category to browse. For cloud/architecture ICONS (AWS/Azure/GCP/Docker/Kubernetes/databases) use listArchitectureIcons; for a sticky/post-it use addWhiteboardElements({type:'sticky'}), not a stencil.. It is categorised as a Read tool in the Stable Baseline MCP Server, which means it retrieves data without modifying state.
Register the Stable Baseline MCP server in PolicyLayer and add a rule for listWhiteboardStencils: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Stable Baseline. Nothing to install.
listWhiteboardStencils is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the listWhiteboardStencils rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for listWhiteboardStencils. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
listWhiteboardStencils is provided by the Stable Baseline MCP server (https://api.stablebaseline.io/functions/v1/cloud-serve/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 184 Stable Baseline tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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