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

With no annotations, the description carries the full behavioral burden and does so well: it discloses that behavior differs by client, that a modal appears and execution resumes in Sequencer/Spark, that no modal can open in external MCP clients, and explicitly warns not to claim a modal opened. This is exactly the kind of environment-dependent side-effect disclosure annotations would not cover.

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?

Front-loaded with purpose and trigger before the environment-specific caveat, and every sentence earns its place. The third sentence is dense but necessary to prevent an incorrect claim of a modal opening.

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 single-parameter, non-mutating gating tool with no output schema, the description covers purpose, trigger, environment-dependent behavior, and the correct fallback action. Nothing an agent needs to call and act on this tool correctly is missing.

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% and the 'reason' parameter is already documented with examples in the schema, so the description need not add parameter detail. It provides no additional meaning beyond what the schema already states, making the baseline 3 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 states a specific verb and resource ('request the user to log in or register') and clearly identifies this as an authentication-gating tool, distinct from the many content-mutation siblings. An agent can tell what it does without opening the schema.

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?

It gives an explicit trigger condition ('when an action requires authentication and the user is not logged in') and then branches on environment, naming the client-specific alternatives (Sequencer/Spark vs. Codex/Claude Desktop/Claude Code/Antigravity). This is unambiguous when-to-use guidance.

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