Accessibility MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the tool 'Run an accessibility audit' which implies a read-only analysis operation, but doesn't disclose any behavioral traits such as execution time, resource requirements, error handling, output format, or whether it modifies any systems. For a tool with no annotation coverage, this leaves significant gaps in understanding how it behaves.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise with just two sentences that efficiently convey the core functionality and input support. Every word earns its place, and it's front-loaded with the primary purpose. There's no redundancy or unnecessary elaboration.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (3 parameters including nested objects, no output schema, and no annotations), the description is incomplete. It doesn't explain what the audit returns, how results are structured, potential limitations, or error conditions. For a tool that performs accessibility analysis, users need more context about output and behavior to use it effectively.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds minimal parameter semantics beyond the schema. It mentions that the tool 'Supports URLs, local file paths, and localhost URLs,' which provides context for the 'url' parameter, but doesn't elaborate on the 'categories' or 'options' parameters. With 100% schema description coverage, the baseline is 3, and the description doesn't significantly enhance understanding of parameter usage or constraints.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Run an accessibility audit') and the technology used ('using Lighthouse CLI'), which distinguishes it from sibling tools like axe_audit and wave_audit that likely use different auditing engines. However, it doesn't explicitly mention what specific accessibility aspects are audited or how it differs functionally from its siblings beyond the tool name.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage by specifying supported input types (URLs, local file paths, localhost URLs), which gives some context for when to use it. However, it provides no explicit guidance on when to choose this tool over alternatives like axe_audit or wave_audit, nor does it mention any prerequisites, exclusions, or performance considerations.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.