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

Beyond the readOnly/destructive annotations, it discloses a non-obvious caveat: boolean starred/archived filtering is unreliable, which prevents a plausible agent failure. It also describes the shape of the returned data (a `fields` array of snake_case column names), adding useful read-side context.

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?

Three sentences: purpose, caveat, return shape — the most decision-relevant item (filter reliability) is placed before the filter inventory. Nothing superfluous beyond the mild title echo at the start.

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?

With 8 optional params, an output schema present, and safe read annotations, the description covers what the agent needs: filter semantics, a reliability warning, and return field format. Minor gaps are pagination defaults and the valid sortBy/sortType values, though those are already documented in the schema.

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, but the description adds real value by naming the exact supported filter set (folder, search, sortBy, sortType, integration) and flagging that boolean filters are not reliable — information the schema's field descriptions do not convey.

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?

States a specific verb (Retrieve) and resource (all contact lists) plus the filtering capability, so the agent knows exactly what it returns. It does not differentiate from the sibling get_list (single list) or from create/update/archive_list, leaving that inference to the agent.

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?

Enumerating the supported filters implies the browse/discovery use case and the "Note: boolean filters (starred/archived) are unreliable" line steers away from a failing path. However, it never says when to prefer this over get_list for a single record, nor any preconditions.

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