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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds non-obvious operational context: a truthful request cost ("2 requests (1 without indexes)") and an authorization-conditional disclosure (write rules and rule tests appear only for tokens that can update the list). These are exactly the traits annotations cannot convey.

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?

Front-loaded with the payload and the routing advice in three tight sentences with no filler. The first sentence is a long enumerated run-on, but every clause maps to a real field group rather than padding.

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 two-parameter read tool with an output schema, the description covers scope, cost, and conditional auth behavior, which is sufficient to call it correctly. Detailing the return payload is somewhat redundant given the output schema exists, leaving minor room for improvement rather than a gap.

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 the baseline is 3; the description goes further by explaining what the includeIndexes switch actually yields (buildStatus plus a per-index usage hint covering sort/filter/search/alias/guard behavior), which makes the flag's tradeoff legible. The `list` identifier format is left entirely to the schema.

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?

Opens with a specific verb+resource and enumerates the exact payload: metadata, JSON schema, flags, tags, itemCount, write rules/rule tests, and indexes with buildStatus and usage hints. An agent can distinguish this from list_lists, get_item, or list_indexes without opening any schema.

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 recommended first call before reading or writing an unfamiliar list" gives explicit when-to-use guidance, and "(only for a token that can update the list)" states a precondition. It stops short of naming alternatives (e.g. list_indexes when only indexes are needed, or the 1-request mode without indexes), so it falls just short of a 5.

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