add_todo

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

With no annotations, the description carries the full disclosure burden: it does state that the tool returns the new todo's id (valuable since there is no output schema) and that icon defaults to 'scroll'. It says nothing about what the optional 'id' parameter means, whether the caller may set it, what happens if the same title already exists, or any permission/side-effect context for a mutating tool.

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 purpose and return value are front-loaded, then parameter semantics follow in a compact block. The long icon key list is long but earns its place because the schema provides no enum for it.

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 six-parameter mutation tool with no annotations and no output schema, the description covers the interesting value constraints and the return value, which is above average. It falls short on the unexplained 'id' parameter and on any statement of side effects or persistence behavior that would be needed for fully confident invocation.

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 has to compensate, and it largely does: it enumerates the accepted CartoonIcons keys, gives the 0..7 range for color, and lists the three timing values with the minutes dependency. The gaps are the 'id' parameter, which is never mentioned, and 'title', which only relies on being obvious from the tool name.

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 a specific verb and resource (create a todo) plus the return value (its id), so the agent knows exactly what the call does. It doesn't distinguish itself from siblings like add_countdown or update_todo, even though the 'timing=countdown' field makes overlap with add_countdown plausible.

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?

There is no explicit when-to-use or when-not-to-use guidance and no reference to the alternative tools for countdowns or habit creation. The only conditional guidance is field-level ('when countdown, use minutes for the duration'), which tells the agent how to fill a parameter but not when to pick this tool.

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