Evaluates UI elements for accessibility issues that automated scanners miss. COST: $0.01 USDC via x402 on Base-compatible EVM network per call. Checks beyond what axe/Lighthouse/WAVE catch at the design stage: - Touch targets below 24×24px (WCAG 2.5.8 AA hard fail) - Touch targets below 44×44px (...
AI agents call evaluate_accessibility to retrieve information from Axcess without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Even though evaluate_accessibility 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
Evaluates UI elements for accessibility issues that automated scanners miss. COST: $0.01 USDC via x402 on Base-compatible EVM network per call. Checks beyond what axe/Lighthouse/WAVE catch at the design stage: - Touch targets below 24×24px (WCAG 2.5.8 AA hard fail) - Touch targets below 44×44px (WCAG 2.5.5 AAA recommended) - Information conveyed by color alone without a secondary indicator (WCAG 1.4.1) - Missing focus indicators on interactive elements (WCAG 2.4.7) - Focus rings thinner than 2px (WCAG 2.4.11) - Focus ring contrast below 3:1 against adjacent background (WCAG 2.4.11) - Interactive elements below the practical usability height floor Args: - elements: Array of 1–50 UI element objects - screen_name: Optional label for the evaluation report Each element requires: element_type. Provide width_px/height_px for touch target checks. Provide uses_color_only + secondary indicator flags for 1.4.1 checks. Provide is_interactive + focus_visible + focus indicator properties for focus checks. Returns: Structured report with: - Per-element scores (0–100) and specific issues - Severity levels (critical/major/minor) with WCAG references - What automated tools miss and why - Concrete fix recommendations - Overall score and verdict (pass/needs_work/fail) - Top issues sorted by severity. It is categorised as a Read tool in the Axcess MCP Server, which means it retrieves data without modifying state.
Register the Axcess MCP server in PolicyLayer and add a rule for evaluate_accessibility: 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 Axcess. Nothing to install.
evaluate_accessibility 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 evaluate_accessibility 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 evaluate_accessibility. 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.
evaluate_accessibility is provided by the Axcess MCP server (sicxz/axcess-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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