tactual-mcp

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 effectively describes key behaviors: it's read-only ('Read-only — navigates to the URL but does not modify the page'), explains how it handles auth-gated targets with statesJson, and mentions skipping browser launch. However, it doesn't cover potential rate limits, error conditions, or performance implications, leaving some gaps.

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 well-structured and front-loaded with the core purpose. Every sentence adds value, such as explaining the return format, read-only nature, usage context, and auth workflow. It could be slightly more concise by integrating some details, but it avoids redundancy and is efficiently organized.

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 (9 parameters, no output schema, no annotations), the description does a good job of covering essential context: purpose, usage guidelines, behavioral traits, and parameter workflows. However, without an output schema, it doesn't detail the return format (e.g., structure of step-by-step actions), which is a minor gap for a tool that returns detailed data.

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?

Schema description coverage is 100%, so the schema already documents all parameters thoroughly. The description adds some context for statesJson by explaining the workflow with analyze_url, but it doesn't provide significant additional meaning beyond what's in the schema descriptions. This meets the baseline for high schema coverage.

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 explicitly states the tool's purpose: 'Trace the exact screen-reader navigation path to a specific interactive target. Returns step-by-step actions a screen-reader user would perform, with modeled announcements, cumulative cost, and the target's role/name at each hop.' This is a specific verb ('trace') and resource ('screen-reader navigation path'), and it distinguishes from siblings like analyze_url by focusing on navigation tracing rather than general analysis.

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 provides explicit guidance on when to use this tool: 'Use this after analyze_url to understand *why* a target scored poorly.' It also details a specific workflow for auth-gated targets, naming analyze_url as an alternative/precursor and explaining how to pass statesJson. This clearly defines the context and alternatives.

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