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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the mutation risk is known. The description adds meaningful behavioral context beyond annotations: it explains the upsert semantics, patch atomicity ('applied in order and atomically — if one fails, nothing is written'), and the exact side effect of completing a task ('True stamps completedAt with the time of the call, never the time the work finished'). This enriches the agent's understanding well beyond the structured hints.

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?

Every sentence earns its place: the first sentence defines the operation, the next two give create and update rules, one covers patch, another covers unlink, and the final states the return. The key decision points are front-loaded before param details, and there is no filler or repetition of schema content.

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?

The description is complete enough for a 9-parameter mutation tool with an output schema. It covers create/update selection, patch semantics, unlink behavior, return value, and the completedAt nuance. Slight gap: it doesn't enumerate every field (matching row title).

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 89%, so the schema already documents nearly all parameters. The description adds value by clarifying the create/update logic for id and name, explaining that patch supersedes note for partial edits, and highlighting that listId null means unlink. It also consolidates the note-rendering detail into the flow of choosing note vs patch. Given the baseline of 3 for high coverage, the description's guidance on mode selection and patch semantics earns a 4.

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 opens with 'Upsert a task,' a specific verb plus resource that immediately distinguishes create from update behavior, and it names the key input that selects between the two modes ('Omit id... Pass id...'). The tool's purpose is completely clear and lets an agent distinguish it from sibling tools like save_list or view_task without needing to inspect schemas.

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?

The description gives explicit when-to-use guidance for both main modes: create requires name and omitted id; update passes id and can take any subset of fields. It also gives precise routing for sub-behaviors: use patch instead of note for partial note edits, use null on listId to unlink. While it doesn't explicitly name sibling altornatives, the create/update mode distinction is effectively the tool's usage contract and leaves little ambiguous.

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