workbench-mcp

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

With no annotations provided, the description carries full burden. It states this is a session-switching operation (implying mutation/state change) and mentions it's equivalent to auth_start_session, but doesn't disclose authentication requirements, permission levels, side effects, or error conditions. It provides some context about semantic intent but lacks behavioral details needed for a mutation tool.

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 with clear sections (purpose, equivalence statement, parameters, returns) and appropriately sized. Every sentence adds value, though the parameter section formatting with dashes is slightly verbose. The information is front-loaded with the core purpose stated first.

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?

For a session mutation tool with no annotations but an output schema, the description provides good coverage: clear purpose, usage guidance, parameter semantics, and return value reference. It lacks details about authentication requirements and error cases, but the output schema reduces the need to describe return values explicitly.

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, the description compensates well by explaining both parameters: 'email' as 'The new user to impersonate' and 'reason' as 'Optional free-text description of why the switch is needed.' This adds meaningful context beyond the bare schema, though it doesn't specify email format constraints or reason length limits.

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 specific action ('Switch the active session') and resource ('to a different user'), distinguishing it from siblings like auth_start_session (which it mentions as equivalent but semantically different) and auth_clear_session/auth_status. It explicitly defines the intent as changing the active user rather than starting fresh.

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 vs alternatives: 'when the intent is to change the active user rather than start a fresh session' and directly references auth_start_session as an equivalent alternative with different semantics. This clearly distinguishes usage contexts between the two tools.

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