garmin_sync

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

The description adds behavioral detail beyond annotations, such as the effect of backfill_days (deepens sleep/HRV history), the resumable nature of backfill, and that it reports freshness. While it doesn't discuss rate limits or side effects, it provides meaningful context for a mutation tool with minimal annotation coverage.

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 primary action, and no unnecessary words. Every clause adds value: the backfill explanation, the resumable nature, and the usage warning.

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?

Given the presence of an output schema (noted in context) and the clarity of sibling relationships, the description covers the essential aspects: purpose, usage conditions, parameter semantics, and behavioral expectations. It is complete for a tool of this complexity.

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?

Even though schema coverage is 0%, the description explains the semantic of backfill_days: 'backfill_days > 0, deepens sleep/HRV history.' This compensates for the lack of parameter descriptions in the schema, though it doesn't mention the default or range (which are in 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?

The description states a specific verb and resource: 'Force a refresh and report freshness, or start a resumable historical backfill.' It clearly distinguishes this from siblings by noting that 'every other tool auto-refreshes,' implying this is the manual override.

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?

Explicit usage guidance is provided: 'Use only if data looks stale.' It also implicitly names the alternative (every other tool auto-refreshes), giving a clear when and when-not to use the tool.

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