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

Annotations declare destructiveHint=true, which an agent would reasonably read as 'overwrites state'. The description meaningfully qualifies that: it fetches the existing snapshot and merges, keeping sticky completed quests/badges so progress isn't wiped. That's genuine value beyond the annotations. It stops short of covering auth/account requirements or the response, so not a 5.

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?

Two sentences, front-loaded with the core action, then the important merge caveat. No filler. Slightly dense parenthetical, but every clause earns its place.

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 destructive, nested-object mutation with no output schema, the description covers the key behavioral risk (merge, not overwrite) and the target store. It omits return/error behavior and any auth prerequisite, but nothing critical to invoking it correctly is missing.

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% (the nested state object is documented as 'Partial or full gamification state to merge in'), so the baseline is 3. The description's 'merge' language reinforces partial-state semantics but adds no field-level detail beyond the schema.

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?

States a specific verb pair (save/merge) and resource (member's Quests/gamification progress) and clarifies the destination is the same store as the app. An agent can immediately distinguish this from the sibling get_quests_progress (read) and save_onboarding_progress (different domain).

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?

Usage is implied – you call this to persist progress – and the read sibling get_quests_progress is implicitly the counterpart, but the description never explicitly says when to use this vs. alternatives or that no read/sync is needed first. Adequate but leaves routing to inference.

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