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

The inline annotations declare idempotentHint=false, but the description explicitly says repeating the call is harmless and moves zero data, which describes idempotent behavior. This is a direct contradiction. Otherwise it adds useful details about transaction scope, collision handling, and token validation, but the contradiction forces a score of 1.

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 front-loaded with the core purpose and then adds prerequisites and edge cases without excessive padding. It is appropriately sized for a complex linking operation, though a few clauses could be tightened.

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 mutation with one parameter and no output schema, it covers the essential behavior: what is transferred, transaction semantics, collision resolution, guest token validation, and repeat behavior. The main completeness gap is that the repeat-behavior claim conflicts with the annotation, leaving the agent uncertain about idempotency.

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 coverage is 100% and already describes guest_token as an edm_… guest token. The description adds meaningful validation context (old, unsigned, or ownerless tokens are refused) and ties the token to the SDK claim from the guest, going beyond the schema.

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: it brings guest-created items (Saved searches, Alerts, Watchers, purchases) into the session account. This is clear enough to distinguish it from most siblings, though it never names a direct alternative like conta_acompanhamento.

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 a prerequisite (bootstrap/CSRF from this browser) and notes that the page performs it right after login, implying when it should be used. However, it does not explicitly say when not to use it or name alternative tools.

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