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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuine behavioral context beyond that: the invariant that only one step is current, and the blocking rule that no step is returned until the user validates a completed phase. It stops short of stating what happens with an invalid or inactive plan_id.

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 dense sentences, front-loaded with the return payload before the state rules. Nothing is redundant, though the long field enumeration makes it slightly heavy for a one-parameter read tool.

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?

With no output schema, the description correctly carries the return-value burden by listing the fields of the working frame, and it explains the not-returned case. It is complete for invocation and interpretation, missing only error/empty-input behavior for plan_id.

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?

One parameter with 0% schema description coverage, so the description carries the burden. It implies plan_id must reference an 'active plan,' which is useful scoping, but it gives no format, ID source, or failure behavior for the single required parameter.

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?

The description opens with a specific verb and resource: 'Returns the working frame of the current step of an active plan,' then enumerates exactly which fields come back (goal, phase/step numbers, instruction, checklist, deliverable, closed-step deliverables, rule). It is unmistakably distinct from plan_status or plan_close_step by content, though it never names a sibling explicitly.

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?

It gives the state-machine condition that determines output ('the first step not closed in the open phase') and the edge case ('when a phase is complete, no step is returned until the user validates the phase'). That is implied usage context, but it offers no explicit guidance on when to pick this over plan_status or plan_list.

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