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

Goes well beyond readOnlyHint, disclosing shared-agent scoping behavior (campaigns/senders limited to the current shared agent and its owner), the meaning of stale and classify_running/classify_done/classify_total, and that criteria is the persisted auto-tagging scope. This is unusually rich behavioral context for a read tool.

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 summary followed by clearly tagged <returns> structure. It is long, but the field-level detail substitutes for a missing output schema, so most sentences earn their place; minor verbosity in enumerating every field.

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?

There is no output schema, so the description fully carries the return-value burden and does so thoroughly, enumerating the response shape and field meanings. Nothing an agent needs to use this correctly is missing.

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?

Zero parameters, so the baseline of 4 applies. The description instead explains return-field semantics (criteria, stale, campaigns, classifiable_campaigns, senders) that inform which tools to call next, adding value even without params.

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+resource (list the user's segment groups) and explains what a segment group is with concrete examples ('Seniority', 'Role function'), distinguishing it from create/update/delete/classify siblings. An agent knows exactly what this returns without opening a 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?

Explicitly says 'Read this first to get a group_id for the rate / people tools', routing the agent to get_segment_rates and query_segment_people, and names update_segment_group as the editing alternative. Both the call condition and the alternatives are stated.

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