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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the mutation profile is covered. The description goes further by disclosing the concrete destructive effect (deleting completed_at), the state transition to pending, and an intentional failure mode for non-closed tasks. It does not cover auth/permission needs, so it is short of a 5.

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: the first sentence delivers purpose, target state, and side effect. The remaining two sentences each earn their place — one routes away from update_task, one states the failure precondition. No filler.

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-param mutation tool with no output schema, the description covers purpose, the competing tool, the destructive side effect, and the failure condition — enough to call it correctly. Minor gap: no indication of what the response returns or whether the revert is itself reversible.

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%, with task_id and workspace_id fully documented in the schema (including the workspace fallback semantics). The description adds no parameter-level detail beyond implying the task must be closed, so the baseline 3 applies.

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 ('Reabre una tarea cerrada') and names the exact resulting state ('vuelve a `pending`') plus the side effect ('BORRA `completed_at`'). It also distinguishes itself from the sibling update_task, so an agent can pick it 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 routing: 'Es el camino correcto para desmarcar algo, no update_task', with the reason the alternative fails (the closing date lingers and keeps the task counted in work history). The precondition ('Falla a propósito si la tarea no estaba cerrada') tells the agent exactly when not to call it.

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