Activity totals

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds the aggregation grain and project-wide scope, which are genuine behavioral facts beyond the annotations, though it does not discuss return shape or refresh/recency of the counts.

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?

Four labeled blocks (Purpose / Not for / Returns / Use when) with no filler, and the routing constraint is front-loaded before the return summary. Every sentence earns its place.

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 zero-parameter, no-output-schema aggregate tool the description covers purpose, routing, and return grain, which is close to complete. A brief note on what the counts include or their freshness window would close the remaining gap.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. No parameters means no risk of mis-invocation through unclear arguments.

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 ('aggregate counts across the activity feed — totals per activity type for the project'), including the aggregation grain. It also explicitly names what it is not (plunk_get_campaign_stats, plunk_get_analytics_timeseries), so an agent can discriminate it from siblings 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?

Explicit 'Not for' entries with sibling tool names plus a 'Use when' clause ('project-wide numbers rather than individual events'). Both the when and the when-not are stated, leaving nothing to inference.

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