add_phase

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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the description's contribution should be the extra context: what a second identical call does, how OrderIndex collisions are resolved, and whether rename/duplicate Name values are rejected. It provides only the 'Admin:' permission hint and says nothing about these ordering/idempotency behaviors, which matter most for a non-idempotent mutation.

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 tight sentences, front-loaded with the admin action, and the second sentence adds genuine domain context rather than padding. Nothing is wasted, though the space saved could have been spent on parameter semantics.

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 non-idempotent mutation with no output schema and zero documented parameters, an agent cannot determine valid OrderIndex values, Name constraints, failure modes, or what is returned. The description covers the concept of a phase but not enough to invoke the tool correctly without guessing at the required fields.

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 0% for all four parameters, so the description carries the full burden — yet it names none of them. Crucially, the required 'OrderIndex' is left completely unexplained (its range, whether gaps are permitted, how it interacts with sibling phases), and 'as_agent' and 'Name' get no mention at all.

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+resource ('add a phase to a plan') so the operation is unambiguous. It also clarifies the domain concept ('phases are an optional structural layer; tasks may be unphased'), which separates it from task-creation siblings like create_task, though it never names an alternative tool.

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 'Admin:' prefix signals a privileged operation, and the note that phases are optional implies this is not always required. But there is no explicit when-to-use/when-not guidance, no prerequisites (does the plan need to be in a particular state?), and no named alternative for restructuring an existing plan.

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