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

Annotations already declare non-read-only, idempotent, non-destructive, closed-world. The description adds a genuine behavioral consequence beyond them: completing a play unlocks the next one in the ranked plan, and the reopen path is disclosed. It stops short of noting permission requirements or whether the optional note is retained, so not 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?

Two short sentences, zero filler. The primary operation is front-loaded and the reopen variant and downstream effect follow immediately.

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 needed and annotations covering the safety profile, the description supplies the two things the agent most needs: the mutation's effect and its downstream unlock. Only the sibling ambiguity with update_play_status keeps it from a 5.

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%, so play_id, done, and note are already documented in the schema, including the done=false reopen semantics. The description adds no syntax or format detail beyond that, so the baseline of 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?

The description states a specific verb and resource ('Mark a growth play as shipped') plus the reverse operation ('or reopen it'), so the agent knows exactly what happens. It does not, however, distinguish this tool from the sibling update_play_status, which plausibly overlaps—that missing differentiation caps it at 4.

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?

Usage is implied rather than stated: completing a play is clearly the way to advance the ranked plan, and the parenthetical signals the reopen path. There is no explicit when-to-use vs when-not guidance and no mention of how this differs from update_play_status, so it lands at minimum-viable.

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