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

No annotations are provided, so the description carries the full burden. It discloses the selection behavior (highest priority, errors first, oldest within priority, blocked subtasks skipped) and the per-call nature of exclude_relative_ids ('does not change the piece state'). It does not mention whether the call mutates anything, but the tool is clearly a read/selection operation and the behavioral rules are well disclosed.

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 two sentences, front-loaded with the core purpose and rules, and every sentence earns its place. It packs the selection rules, the sibling reference, the usage directive, and the parameter guidance without redundancy.

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 selection tool with no output schema and no annotations, the description covers the selection rules, the relationship to GetNextTaskTool, and the optional exclusion parameter. It does not describe the return value shape, but since there is no output schema and the tool is a simple 'get next subtask' operation, the missing return details are a minor gap rather than a critical one.

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 the schema already documents all three parameters. The description adds meaning for exclude_relative_ids by explaining its purpose ('subtasks you are stuck on') and its per-call scope, which is useful. However, it does not add much beyond the schema for account_code or story_relative_id, so a 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 verb ('Get the next subtask to work on'), a specific resource ('inside one Story'), and explicitly distinguishes it from the sibling GetNextTaskTool by referencing the same rules. It also tells the agent to call this instead of scanning subtasks itself, which makes its purpose unmistakable.

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 says 'Inside a Story call this instead of scanning its subtasks yourself,' which is a clear when-to-use instruction. It also names the sibling GetNextTaskTool as the source of the same rules, and explains the exclude_relative_ids parameter as a way to skip subtasks the agent is stuck on. This is strong usage guidance.

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