get_apg_pattern
ENTRY POINT for building a composite component. Returns the verbatim W3C APG card (about, keyboard interactions, examples), the ARIA contract for its roles, the native HTML elements that carry them, and suggested_queries (ACT searches) to run next. Also returns applicable_scs: the WCAG criteria t...
This record as markdown: /tools/a11y-assist-mcp/get-apg-pattern.md
What get_apg_pattern does on A11y Assist
AI agents call get_apg_pattern to retrieve information from A11y Assist without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
name | string | Yes | APG pattern name — e.g. dialog, tabs, combobox, accordion, listbox, disclosure, menubutton. Aliases like "modal" → dialog are accepted. Call list_apg_patterns t |
level | string | — | Target WCAG conformance level (cumulative). Stamped into the suggested ACT queries. |
Parameters from the server's own tool schema.
Why get_apg_pattern is rated Low
Even though get_apg_pattern only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs get_apg_pattern safely
PolicyLayer is an MCP gateway: it sits between your AI agents and A11y Assist, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For get_apg_pattern, this is the rule to start with:
get_apg_pattern is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect A11y Assist, apply this rule, and every get_apg_pattern call is checked against it from then on.
Questions about get_apg_pattern
ENTRY POINT for building a composite component. Returns the verbatim W3C APG card (about, keyboard interactions, examples), the ARIA contract for its roles, the native HTML elements that carry them, and suggested_queries (ACT searches) to run next. Also returns applicable_scs: the WCAG criteria that apply from the component's structure alone (the floor) at the chosen level, plus a tiered verification checklist (axe / agent / human) and a count of further criteria that depend on the content you add. For native primitives (text input, link, image) use get_aria_role instead. It is categorised as a Read tool in the A11y Assist MCP Server, which means it retrieves data without modifying state.
get_apg_pattern accepts 2 parameters: name, level. Required: name. The full parameter table on this page comes from the server's own tool schema.
Register the A11y Assist MCP server in PolicyLayer and add a rule for get_apg_pattern: 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 A11y Assist. Nothing to install.
get_apg_pattern 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 get_apg_pattern 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 get_apg_pattern. 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.
get_apg_pattern is provided by the A11y Assist MCP server (a11y-assist-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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