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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the bar is lower, yet the description adds real value the annotations cannot: atomic all-or-nothing semantics and that the error identifies the offending entry. It does not mention any permission/auth requirement or rate limiting, so it stops short of 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?

Three tight sentences, front-loaded with the capability and the cap, then the atomicity guarantee, then the routing advice. No filler or repetition of schema detail.

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?

A single-parameter batch write tool with an output schema, so return format need not be described. The description covers capability, limit, failure semantics, and sibling routing — everything needed to call it 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 100%, so the nested entry fields (note, tags, value, values, topicId, occurredAt) are fully documented in the schema. The description only restates the 1–50 bound already expressed by minItems/maxItems, adding no new parameter meaning. Baseline 3 applies.

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 ('Records up to 50 entries in one call') plus concrete scope examples (a meal's foods, a backlog). The batch framing directly distinguishes it from the sibling log_entry, so an agent can route without opening either 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?

Explicitly names the alternative and the condition that selects it: 'Prefer this over repeated log_entry calls.' The meal/backlog examples further clarify the intended multi-entry scenario, leaving nothing to inference.

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