Leveling phases

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

readOnlyHint=true already establishes this as a safe read, and the description adds useful context beyond that: it is static reference data whose 'Level ranges come from quest area levels', i.e. a derived lookup table rather than live character state. No auth, mutation, or rate-limit concerns are implied, consistent with the annotation, though pagination/ordering behavior is not mentioned (not relevant for a 0-param static table).

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?

A single dense sentence, front-loaded with the resource name and followed by the enumerated payload. Every clause carries information needed by the agent given there is no output schema, though the long comma-heavy list is slightly harder to scan than a short bulleted structure would be.

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?

With no output schema and no parameters, the description carries the full burden of describing what comes back, and it does so thoroughly (phases, ranges, checkpoint, passives, Spirit, gem level, quest rewards). It is complete enough to call correctly; only the concrete return shape/field names are left unspecified, which is a minor gap for a static reference table.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. The description correctly implies a parameterless reference lookup with no input filtering.

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 names a specific resource (leveling phases for a league-start character) and enumerates its exact contents — phases, level ranges, checkpoint level, passive points, Spirit, gem level, quest rewards. It also ties itself to the sibling check_build via the 'checkpoint level to run check_build at', which helps an agent place it among the build tools. It stops short of a stated verb ('returns/reference lookup'), but the scope is unambiguous.

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?

There is no explicit when-to-use, when-not-to-use, or alternatives guidance. Only the phrase 'for a league-start character' implies context, and the check_build mention implies a downstream workflow step, but nothing tells the agent whether to prefer this over create_build_guide, evaluate_build, or plan_passive_tree.

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