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

Goes well beyond the annotations: it discloses that connecting copies nothing and only grants read/consult access, and imposes a consent/privacy notice before connecting Carlos's brain (queries reach his server, email excluded). What it does not cover is failure behavior for an invalid code or what an already-connected brain returns, which the annotations (idempotentHint, openWorldHint) only partly imply.

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, front-loaded with the action and its precondition, then the privacy obligation, then the non-copying semantics. Dense and largely waste-free, though the privacy clause is embedded mid-paragraph rather than structured as a separate step.

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 two-parameter mutation with no output schema, the description covers consent, data flow, privacy disclosure and parameter sourcing — enough to call it correctly. Minor gaps remain on invalid-code handling and what the user sees after a successful connection.

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%, so the baseline is 3; the description earns the extra point by routing `id` to the list_brains catalog and framing `code` as owner-issued, which clarifies where each value comes from. The "o" construction also communicates that the two optional parameters are alternatives, something the schema itself does not state.

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?

States a specific verb and resource ("Conecta otro cerebro al del usuario") and immediately contrasts with the catalog path handled by list_brains. An agent can distinguish it from disconnect_brain, share_brain and list_brains without opening any 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?

Explicit gating condition ("solo cuando él lo pida") plus the two mutually exclusive paths: `id` from the catalog via list_brains, or `code` supplied by the owner. This is when-to-use and alternative-selection guidance in one sentence.

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