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

Annotations only supply destructiveHint=true, so the description carries most of the burden. It adds a genuine behavioral constraint (the assignee one-of requirement), but omits auth/permission needs, side effects such as notifications to the assignee, and what is returned on success.

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?

Two short sentences, no filler; the assignment requirement is front-loaded right after the core purpose. Every clause carries information.

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 9-parameter mutation tool with no output schema, the description covers the most important constraint but not the response shape or failure modes. Also pthe allowed task 'type' values and due-date formats are left entirely to the schema.

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 78%, so the schema already documents most fields (name, type enum, dueDate, dueDateTime, remindSecondsBefore). The description adds value by stating the cross-field constraint that assignedUserId or assignedTo is required — a relationship absent from the schema's required list.

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 ('Create a task'), names the target entity it attaches to ('on a contact'), and repeats the underlying API operation (POST /v1/tasks). This is immediately distinguishable from fub_update_task and fub_list_tasks without inspecting schemas.

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 supplies one real usage rule: an assignee must be given via assignedUserId or assignedTo. It says nothing about when to prefer this over alternatives, prerequisites (e.g. the person must already exist), or when creation would fail.

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