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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds real value beyond that: the append/replace distinction, the requirement to read before replacing, and the data-preservation rule to keep ^task markers intact. It still omits return behavior and what happens on append to a non-existent note.

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 short sentences, front-loaded with the core operation and followed by the critical safety constraint. Nothing is wasted.

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?

For a mutation tool with 0% schema coverage and no output schema, the description covers the operation and the key preservation rule but leaves date handling, defaults, and error/edge behavior unaddressed. Adequate but with clear gaps.

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 carry parameter meaning. It conveys the semantics of the mode enum values indirectly ('append'/'replace') but says nothing about the date parameter (expected format, default when omitted, maxLength 10) or content limits.

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 pair and resource: 'Append to or replace a day's note.' This clearly distinguishes it as the write counterpart to get_notes, though it does not name that sibling explicitly.

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?

'Read before replacing' gives one actionable pre-condition for replace mode, which is genuinely useful guidance. However, there is no guidance on choosing append vs replace, no mention of reading via get_notes, and no exclusions, so usage is only partially covered.

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