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

Annotations already declare readOnly/idempotent/non-destructive, and the description partly echoes that ('Read-only. Does not change anything'). It earns credit for disclosing traits annotations cannot: returned fields (property ID, display name, account, visible Google accounts), deduplication of properties visible to multiple connections, and the GA4-only filter.

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 with the routing condition, then the return shape, then caveats. Efficient overall, but the final two sentences ('Read-only. Does not change anything in Google Analytics.') restate the annotations and could be trimmed.

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?

An output schema exists, so return values need not beSpecified; the description nonetheless previews them helpfully. With safety covered by annotations and both params documented in the schema, nothing an agent needs in order to select or call this tool 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?

Schema description coverage is 100% with only two optional params, so the schema fully documents cursor and connection_id. The description adds no additional semantics about when or how to supply them, which is the baseline-3 case rather than a deficiency.

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 and resource ('List Google Analytics properties') and immediately narrows scope: GA4 only, UA excluded, one entry per property. An agent can distinguish this from the report-oriented siblings (run_report, compare_report) without 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?

Gives explicit trigger conditions: when the user asks which GA sites/apps they can access, or needs the exact property_id for another call. It also states an exclusion (Universal Analytics not included). It does not name a sibling or alternative to route to, so it falls short of a full when/when-not/alternatives statement.

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