sync_index

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

With no annotations, the description carries full burden. It usefully discloses that entries are removed ("drop deleted/moved mail") and gives a performance characteristic, but says nothing about auth requirements, re-run semantics for the years window, 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 with zero padding, and the core action is front-loaded ahead of the performance note. Every sentence earns its place.

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 two-optional-parameter sync tool with no output schema and full schema coverage, the description covers the essential what and cost. Nothing critical to invoking it correctly is missing, though pointers to index_stats would be a bonus.

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 both parameters (years, account) are already documented in the schema. The description adds no syntax, default, or interaction detail beyond that, so the baseline 3 applies.

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: pulling new mail into the local index and dropping deleted/moved mail. It is clearly distinguishable from read-only siblings like search_index, though it never names an alternative explicitly.

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?

"Incremental runs take seconds" implies the tool is cheap to re-run, hinting at usage context, but there is no explicit when/when-not guidance and no mention of prerequisites such as running this before search_index.

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