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

The annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is largely pre-supplied; the description's 'this tool changes nothing' mostly restates it. Beyond that it adds pagination context and a note that deleting a folder does not delete its contacts, but that note concerns an action this tool does not offer, so it is dead weight here rather than useful disclosure.

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 first paragraph is tight and front-loaded with scope plus the routing rule. The second paragraph then spends roughly half the definition documenting create/update/delete/add_contacts/remove_contacts, none of which exist in this tool's enum, so those sentences do not earn their place and actively compete with the two real actions.

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-action read tool with a fully documented nested schema and annotations, the description covers the required scope, the sibling boundary, and the action list an agent needs. The only shortfall is that the surplus write-action documentation invites an agent to attempt unsupported actions.

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%, and every parameter already carries an action-tagged description in the schema, so the description adds little new meaning. It restates page/per_page/folder_id without format, default, or limits beyond what the schema already says (default 20, max 100, color enum). Baseline 3 applies when the schema does the heavy lifting.

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 opening sentence names the resource and the two read actions (list, list_contacts) and explicitly names the sibling `folders_manage` that owns every write. That distinguishes it cleanly from siblings. However, the second paragraph reopens with 'Manage contact folders' and enumerates create/update/delete/add_contacts/remove_contacts, which blurs what the tool actually does and is only rescued by the first paragraph.

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 when-to-use and when-not-to-use rule: all writes are on `folders_manage` and are 'refused here'. The alternative tool is named directly, so an agent has no reason to guess.

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