add_tiles_to_split

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the mutation effect ('Add additional tiles'), the consequence ('invalidates the MECE validation'), and the required follow-up action ('requires re-verification'). However, it doesn't mention potential side effects like whether this operation is reversible, what permissions are needed, or rate limits, leaving some behavioral aspects uncovered.

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 perfectly concise with just two sentences that each earn their place. The first sentence states the purpose and usage context, while the second provides critical behavioral information about consequences. There's zero wasted language or redundancy.

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 no annotations and no output schema, the description does well by explaining the purpose, usage context, and important behavioral consequences. However, it doesn't describe what the tool returns or provide details about error conditions, which would be helpful given the lack of output schema. The description is mostly complete but has minor 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 100%, with both parameters clearly documented in the schema. The description adds no additional parameter semantics beyond what's already in the structured schema. According to the scoring rules, when schema coverage is high (>80%), the baseline is 3 even with no parameter information in the description.

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 clearly states the specific action ('Add additional tiles'), target resource ('to an existing split'), and purpose ('when you realize a category was missed'). It distinguishes this from sibling tools like 'split_tile' (which creates new splits) and 'update_tile' (which modifies existing tiles).

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 explicitly states when to use this tool: 'when you realize a category was missed.' It also provides an important exclusion: 'This invalidates the MECE validation and requires re-verification,' which helps the agent understand this should not be used if MECE validation is currently valid. This gives clear context for when to use versus alternatives like 'split_tile' for initial splits.

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