fitbit_get_weight

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

With no annotations, description carries full burden. It discloses default caching behavior, necessity of prior sync, sparse nature of data, and return format (one entry per weigh-in with weight_kg, bmi, fat_pct). No contradictions.

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?

Concise, uses bullet list for arguments, each sentence provides unique value. No 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?

Tool has output schema, and description lists return fields (weight_kg, bmi, fat_pct). Covers cache behavior, date defaults, and live mode. Fully complete for a retrieval tool with 3 parameters.

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 0%, but description compensates fully: explains all three parameters (start_date, end_date, live) with defaults, format ('YYYY-MM-DD', 'YYYY-MM', '30d'), and behavior.

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?

Description clearly states 'Get weight log entries (weight, BMI, body fat percentage)', specifying the verb 'Get' and resource 'weight log entries'. Sibling tools (e.g., fitbit_get_activity, fitbit_get_sleep) are for other data types, so this tool is well-distinguished.

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?

Guidance on cache vs. live fetching is explicit: 'Returns data from the local cache by default. Use live=True to fetch from Fitbit API. Run fitbit_sync first to populate the cache.' Also notes data sparsity. Does not explicitly compare to siblings, but their distinct purposes make that implicit.

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