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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered; the description adds the 'FREE (key)' cost signal and enumerates what each mode returns, including permission-scoped elements ('what you may do', 'which you may write', 'sublists you are limited to'). It stops short of stating authorization prerequisites (e.g. what happens if list_id is unknown or inaccessible), leaving a small gap.

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 no-list_id / with-list_id parallel structure is front-loaded and scannable, and every clause names a distinct returned element rather than padding. The second half is dense with comma-separated items, which is efficient but slightly harder to parse than the opening clause.

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 no output schema, the description carries the return-value burden and discharges it by enumerating the fields of both response shapes. For a read-only two-parameter discovery tool, an agent has everything needed to call it correctly and know what comes back.

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% and the list_id description is already documented, but the description adds genuine meaning by contrasting the two calls and describing the payload difference between them. It says nothing about the language parameter despite that enum affecting tell_your_user output, which is the remaining gap.

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 uses a specific verb (describe) plus a precisely scoped resource (a list) and explicitly splits the two modes: no list_id returns the lists shared with you, list_id returns that list's schema. It names concrete returned artifacts (columns, statuses, sublists, pipelines, filter conditions), which separates it from siblings like describe_setup and check_list without the agent 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?

It gives an explicit directive, 'Call it before working on a list,' establishing this as the prerequisite step before the many mutation siblings (add_records, update_records, fix_list). The mode split also functions as when-to-use guidance: omit list_id to discover lists, supply it to inspect one.

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