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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so 'It does not write' merely restates structured data and earns no credit. No additional behavioral context (auth needs, freshness of projections, caching) is provided beyond the safety profile.

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 terse sentences with the mode marker and the returned payload front-loaded; every clause carries information and nothing is padded.

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 tool with no output schema and zero parameter documentation, the description should at minimum explain what already_enrolled does and when each state applies. It covers the payload at a high level but leaves the invocation semantics incomplete.

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 0%, so the description carries the full burden for both parameters. 'This key's' loosely implies profile_id identifies the watch key, but already_enrolled is never explained, leaving half the parameters undocumented anywhere.

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 (return) and a concrete payload (Eligibility Watch trend, projected dates, rule-change notes), which is more specific than the title. It distinguishes itself from write siblings via 'It does not write' but never names an alternative tool, so it stops short of full sibling differentiation.

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?

There is no when-to-use guidance and no alternatives named. The agent is left to infer from 'READ' that this is the retrieval counterpart to watch_save_checkin, but nothing states when to prefer it over check_eligibility or get_rule_changes.

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