log_custom_food

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

With no annotations, the description carries the full burden and does well: it explains automatic meal-window matching, the SNACKS fallback, ID format differences, and the 400 error on source mismatch. It omits duplicate/idempotency behavior and whether an existing entry is overwritten, which matters for a write tool.

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?

Well structured with source and lookup cues front-loaded, but there is mild redundancy between the title line and 'Adds a food entry to the nutrition log', and the Args block duplicates parameter info. Still, every section serves a purpose and it is easy to scan.

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?

An output schema exists, so return values need not be explained, and the description covers meal resolution, source namespaces, ID formats, and a failure mode. The notable gap is how this tool relates to log_food and upsert_and_log, which an agent needs to choose correctly.

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 0%, so the description must compensate, and it does: it documents all six parameters with concrete formats (YYYY-MM-DD, HH:MM:SS with account timezone), default values, and enum semantics for source. It even gives example ID shapes for both namespaces, adding meaning well beyond the bare 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 and resource ('Log a food item to a meal on a date') and elaborates what it does. However, it never distinguishes itself from its close siblings log_food and upsert_and_log, which appear to do overlapping things, so an agent cannot tell them apart from the description alone.

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?

Gives clear routing guidance: use get_custom_foods for GARMIN IDs and search_foods for FATSECRET IDs, and warns that a wrong source yields a 400. It lacks any when/when-not guidance relative to log_food or upsert_and_log, so the alternative-selection story is incomplete.

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