update_todo

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

No annotations exist, so the description carries the full behavioral burden. It does valuable work by disclosing partial-update semantics ('没传的字段保持原样') and side-effect scope ('完成状态不受影响'), but says nothing about what happens when the id does not exist, whether fields can be cleared, or what is returned.

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, both load-bearing: the first defines the operation and its partial-update guarantee up front, the second prevents a concrete misuse. There is no filler or restated naming.

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?

Given a simple six-parameter mutation tool with no annotations and no output schema, the description covers purpose, partial-update behavior, and the duplicate-creation hazard, which is substantial. It is still incomplete on two parameters (id, minutes) and on failure behavior, gaps an agent will notice at call time.

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% across six parameters, so the description must compensate. It names four of them (title, icon, color, timing) but supplies no value semantics for any of them, and it omits id and minutes entirely, including the relationship between the timing mode and minutes, which the agent is left to guess.

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 plus resource ('改一条待办') and enumerates the mutable fields (标题/图标/颜色/计时模式), so an agent knows exactly what this does without opening the schema. It also distinguishes itself from the closest confusion risk, add_todo, in the same breath.

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 names an explicit alternative to avoid (add_todo) and gives the reason (a new id creates a second todo), which is real routing guidance. It also implicitly routes completion changes elsewhere by declaring 完成状态不受影响, though set_todo_done and delete_todo are never named and the wording leaves the reader to join the dots.

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