Add work package watcher

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

The description discloses idempotency ('Calling twice is harmless: the second call reports changed: false'), permission requirements, and error behavior (422 on user visibility violation). These go well beyond the annotations (idempotentHint, etc.) and add valuable behavioral context. No contradiction 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?

The description is dense but every sentence earns its place. It uses clear sections (purpose, usage, return value, pitfalls, cross-references) and front-loads the main action. No fluff or repetition.

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?

Despite having an output schema, the description still summarizes the return values. It covers prerequisites, error conditions, permissions, idempotency, and related tools. For a tool of moderate complexity with two parameters and a clear output schema, this is fully complete.

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% with detailed parameter descriptions already. The description adds extra nuance for user_id (the 'me' string is not accepted, permission differences when adding oneself vs. others) and for work_package_id (source of valid IDs). This elevates it slightly above the high-coverage baseline.

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+resource: 'Subscribe a user to a work package's notifications.' It clearly distinguishes the tool from siblings by contrasting watching with assignment ('Watching is not assignment — use update_work_package(assignee=...) for that') and cross-referencing remove_work_package_watcher as the reverse operation.

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?

Explicitly states when to use: 'Use this when someone should be kept in the loop on a ticket without being assigned to it.' It also provides exclusions (assignment use case), alternatives (remove_work_package_watcher), and prerequisite conditions (user must have view access, permission needed for adding others). This is a model of usage guidance.

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