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

Annotations already establish that this is a non-read-only, non-idempotent, non-destructive mutation. The description adds useful behavioral context beyond annotations: XP is awarded, result verification starts, only OPEN quests qualify, and an explicit user request is required.

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 front-loaded with the action, then effects, prerequisites, ID source, and the safety warning. Every sentence carries operational value, with no filler.

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 single-parameter mutation tool with no output schema and existing annotations, the description covers purpose, effects, preconditions, parameter source, and call restriction. An agent has everything needed to decide when and how to call it.

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?

There is only one parameter, and schema description coverage is 100%, so the schema already documents that questId comes from quests_and_issues with kind=quest. The description repeats that source but does not add further syntax or format detail, making the baseline 3 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 verb and resource ('Mark one of the user's quests as implemented') and immediately adds the key outcome ('Awards the quest's XP and starts result verification'). It clearly distinguishes quest completion from sibling tools like complete_plan_step by focusing on quests and referencing quests_and_issues for IDs.

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 explicit preconditions ('Only quests with status OPEN can be completed'), tells the agent where to obtain the required ID ('get quest ids from quests_and_issues with kind=quest'), and adds a strong usage restriction ('Never call this without an explicit user request'). This leaves little room for incorrect invocation.

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