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

Annotations already establish this is a mutation (readOnlyHint=false) and non-destructive (destructiveHint=false). The description adds valuable behavioral context beyond annotations: it marks emails as consumed, links them to a move, restricts effects to 'new' items, and notes GM-only access. No contradictions with annotations.

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?

Three sentences with zero fluff: action, usage timing, and scope condition. The core function is front-loaded, and every sentence earns its place. The GM-only note is concise and necessary.

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 simple 2-parameter tool with an output schema and annotations, the description covers when to use, what it does, and its scope. It could clarify what 'consumed' means for the inbox (e.g., removal vs. archiving) or define 'new', but these are minor given the output schema likely conveys return state.

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 both parameters are already fully documented. The description adds a behavioral constraint ('Only new items... affected') that indirectly relates to itemIds, but it does not add parameter-specific meaning beyond schema. Baseline 3 is appropriate.

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 action ('Mark inbox emails consumed and link them to the move'), a clear resource and target, and the use context ('after play_create_move / play_update_move'). It distinguishes from sibling PBEM tools by specifying 'consumed' and 'collated into', which implies a state change tied to a move rather than simple dismissal or resolution.

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 explicitly tells the agent when to use the tool: after play_create_move/play_update_move when building a move from emails. It also gives a scoping condition ('Only new items... affected'). It does not list alternatives or explicit when-not-to-use scenarios, but the context is clear enough for correct routing.

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