Tap

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

Annotations declare safety properties (readOnlyHint: false, destructiveHint: false, openWorldHint: true). The description adds valuable behavioral context not in annotations: the return value structure '{url, title}' and redirect detection logic ('If url differs from requested, a redirect occurred').

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?

Three sentences efficiently cover: (1) core action, (2) prerequisite/Alternative check, and (3) return value semantics with redirect detection. Zero waste, front-loaded with the action, and appropriately structured for quick parsing.

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 absence of an output schema, the description adequately documents the return structure '{url, title}' and explains redirect behavior. For a single-parameter navigation tool, this covers the essential behavioral surface, though it could explicitly clarify that 'title' refers to the document/page title.

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?

With 0% schema description coverage for the 'url' parameter, the description partially compensates by mentioning 'Navigate to a URL' in the opening sentence, implying the parameter's purpose. However, it lacks explicit parameter documentation, format constraints, or examples that would fully compensate for the schema gap.

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 opens with the specific verb 'Navigate' and resource 'URL', clearly defining the core action. It effectively distinguishes itself from sibling tool tap.run by specifying this is the fallback when no specific tap exists for the site/task.

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?

Provides explicit when-not-to-use guidance: 'Before calling this, check tap.list — if a tap exists for this site/task, use tap.run instead.' This clearly directs the agent to the preferred alternative, preventing incorrect tool selection.

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