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

Beyond the annotations, the description discloses important behavioral constraints: text must be verbatim and unmodified, with no summarizing, rewriting, or trimming, and content must never be invented. It also explains that the title is a rough draft the user will rewrite, which is exactly the kind of context annotations cannot provide.

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 description is front-loaded with the action and use case, then moves into content-fidelity rules and finally batching behavior. Despite being longer than average, every sentence adds actionable constraint or context, and there is no filler.

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 simple send-only tool with no output schema, the definition covers the action, trigger phrases, verbatim-content rule, title semantics, and multi-note behavior. Nothing an agent needs in order to call it correctly is missing.

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 100%, so the baseline is 3, but the description adds meaningful semantics for the two key parameters: text must be the verbatim full text of one chat message, and title is a rough label draft of 20 characters or less. The source parameter is not discussed in the description, though the schema documents it with a default.

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?

The description states a specific verb and resource: send a note to the user's ThinkSpace inbox, and identifies the target apps (iPhone, iPad, Mac). There are no sibling tools, but an agent can immediately tell what this tool does and where the content goes.

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 explicitly names when to use the tool, including example user phrasings in Japanese and English, and gives the batch rule: call once per note for multiple notes. No alternatives are needed because no sibling tools exist, but the usage trigger is unambiguous.

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