End combat

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

The description explains the effect on combat state (round 0, not active) and that combatants and initiatives are preserved, which goes beyond the destructiveHint annotation. It also discloses that deletion requires permission, adding context to the destructive nature. The idempotentHint and readOnlyHint are not contradicted; in fact, the explanation of 'keeps its combatants and initiatives' supports the non-destructive stop behavior.

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 consists of only two sentences, with the core action front-loaded in the first sentence ('End a combat encounter: it stops...') and the alternative and caveat in the second. No unnecessary words or repetition of annotation data.

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 3-parameter tool with full schema coverage and clear annotations, the description covers the primary behavior, the delete alternative, the permission requirement, and the fallback to the active encounter. An agent has all necessary information to invoke the tool correctly, even without an output schema.

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?

Although the schema already documents each parameter, the description adds extra meaning beyond the schema descriptions: it explains that without combatId the active encounter is used, and that deleteEncounter changes the operation from stopping to deleting, plus the permission caveat. This adds value over the raw schema, which was already 100% covered.

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 clearly states the tool ends a combat encounter, specifying the resulting state (round 0, not active) and that it retains combatants and initiatives. It explicitly distinguishes between stopping and deleting via the deleteEncounter parameter, which is a key differentiator from sibling tools like start-combat or delete-encounter.

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 contrasts the default behavior (stop) with the deleteEncounter alternative, and even references Foundry's own End Combat to clarify semantics. It also notes that deletion is refused without a proper permission level, so an agent knows deletion may require permissions. It doesn't explicitly say 'use this to end an active combat' but that is clearly implied.

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