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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful non-annotation context: the event UUID must come from search_events because MCP does not persist selected event context, and date filters are global across actions. Return shapes are covered by the existing output schema.

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 core action, then a tight bulleted dispatch list, then the two constraints that matter (event_id provenance, date filter scope). No filler sentences; every line carries information an agent needs.

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 multi-mode read tool with a rich output schema, the description covers what each mode returns, how to obtain the required event_id, and how the date range behaves. Nothing an agent needs in order to select the right action and call it 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?

Schema coverage is 100%, so baseline would be 3, but the description genuinely extends the enum: the schema only says 'Which analytics report to read' while the description spells out the content of each of the six action values. It also restates the date-format and start_date-only semantics, which the schema already covers.

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 ('Read analytics for the provided event') and then enumerates all six report types with the concrete metrics each returns. This makes it trivially distinguishable from siblings like read_registration, read_attendees, or read_flow_results, which cover different domains.

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 routes the agent to search_events for the required event_id, which is the key prerequisite. It also clarifies that date filters apply to every action. It stops short of naming which sibling tool to use for adjacent data (e.g. read_registration vs. the registrations action), so it's clear context but not full alternative routing.

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