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

Annotations declare readOnlyHint=false, destructiveHint=false and idempotentHint=false, so the safety profile is partly given. The description adds material context the annotations cannot carry: the amendment changes nothing until explicit user acceptance, and closed steps/validated phases are immutable. It stops short of describing atomicity of multi-operation batches or what a rejected amendment returns.

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-loads the core purpose in the first clause, then uses a tight bulleted enumeration of operations, then closes with the critical staging/immutability caveat. No sentence is filler; the structure matches how an agent would scan for the applicable op.

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 tool with three required params, no output schema and 0% schema description coverage, the definition covers operations, constraints, and the handoff to plan_validate. Remaining gaps are minor: batch semantics when multiple operations are passed, and the behavior when the user declines the amendment.

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%, so the description must carry the load, and it largely does by mapping each op (add/remove/modify/move) to the fields it consumes: phase, position, step, step_id. It does not explain plan_id or justification, and the nested PlanStepIn fields (title, instruction, checklist, deliverable) are never mentioned.

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?

Names a specific verb and resource ('Proposes a change to an active plan') and immediately enumerates the four operation kinds with the exact fields each requires. An agent can distinguish this from plan_create (new plan) and plan_validate (accepting the amendment) 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?

States the implicit boundary conditions explicitly: 'Closed steps and validated phases cannot change' and routes corrections to the alternate path ('add a correction step'). It also tells the agent the amendment is inert until the user accepts it in the dashboard or via plan_validate, which is exactly the when-to-use context an agent needs.

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