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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds valuable context by warning that on success it 'immediately replace[s] any stored mcp_token' and that the 'new token is tied to a different account.' This goes beyond the structured annotations to disclose a specific side effect and account-switching behavior, earning a 4.

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 two sentences long, front-loads the main purpose, and every sentence adds meaningful information. There is no fluff or redundancy. It is an example of concise, well-structured documentation.

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 2-parameter auth tool with no output schema, the description covers the core purpose and side effect, but it lacks critical flow context: it does not explain that the code must come from a prior login-start step, nor does it describe what the tool returns on success. Given the large sibling family, an agent might not understand the full lifecycle, so completeness is only adequate.

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% for both parameters (code and redirect_url), so the schema already explains their meaning. The description only mentions 'Google OAuth code' and does not add new semantics for redirect_url. With full schema coverage, the baseline of 3 is appropriate.

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 a specific action: 'Exchange Google OAuth code for MCP token.' This identifies the verb (exchange), the input (Google OAuth code), and the output (MCP token), and it distinguishes this tool from siblings like dex_auth_google_login_start and dex_auth_google_login_poll, which handle initiation and polling rather than token exchange.

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 when a Google OAuth code is available, but it does not explicitly state when to use this tool versus alternative auth tools, nor does it mention prerequisites like having first called dex_auth_google_login_start. The guidance is implicit rather than explicit, so it falls short of a 4.

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