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

Annotations already indicate this is not read-only and not destructive. The description adds behavioral detail by stating it sets round 1, turn 0, returns the combat state, and that includeContext appends tactical context (combatant position, nearby enemies, line of sight, ASCII map). This goes beyond the schema and gives agents a clear picture of the tool's effects.

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?

The description is compact, front-loaded with the core action and prerequisites, and every clause adds useful information. No filler or redundant restatement of the title.

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?

The description covers the essential usage prerequisite, the initial state, and return behavior. With no output schema, the note about returning combat state and tactical context is valuable. A minor gap is that it doesn't mention what happens if combatId is omitted and no active combat exists, but the schema already covers the fallback behavior.

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 coverage is 100%, so the baseline is 3. The description adds value by elaborating on includeContext: it explains the default (true) and exactly what tactical context is appended. It also reinforces that combatId can be omitted to use the active combat, matching the schema's description.

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: 'Begin combat (round 1, turn 0).' It clarifies the initial state and the ordering prerequisite ('Call AFTER adding combatants and rolling initiative'), which clearly distinguishes this from sibling tools like combat-create, combat-add-combatant, and combat-roll-all-initiative.

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?

Explicit sequencing is provided: 'Call AFTER adding combatants and rolling initiative.' This gives a clear condition for when to use the tool. It does not name specific alternatives or explain when not to use it, but the prerequisite is strong context.

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