Write daily note

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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is covered. The description earns credit by going beyond them: it discloses that writes go to the live MFP account ('synced to your account') and that the default behavior replaces the existing note unless append is set, which is precisely the destructive consequence an agent needs spelled out.

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?

The scope and sibling distinction come first, then a compact three-line parameter block. Every clause carries information — no restatement of the tool name, no filler — and the ragged trailing whitespace is cosmetic.

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, the description need not explain return values, and annotations already cover the safety profile. It covers what is written, where it lands, and all three parameters, leaving only minor gaps such as whether the call errors when the day does not yet exist or what confirmation is returned.

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 carries the full burden and largely meets it: text as the note body, append as 'add to the existing note on a new line instead of replacing it', and date as YYYY-MM-DD defaulting to today. The format and default details for date are genuine additions the schema does not provide; only the exact type expectations for text are left thin.

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 ('Write the MyFitnessPal daily diary note') and pins down exactly which artifact is touched (the free-text 'Notes' box at the bottom of the day). It also names the sibling it must not be confused with (fitness_log_feel, local-only), so an agent can route correctly without opening any schema.

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?

It distinguishes this tool from fitness_log_feel and explains the replace-vs-append decision point, which is the main usage choice an agent faces. It stops short of naming fitness_get_note as the read counterpart or stating when not to write at all, so it is clear context rather than a full when/when-not/alternatives map.

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