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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description's only added context is the word "stored", implying this reads a locally cached range rather than hitting the live API — a small but genuinely useful distinction. No mention of scope, staleness, or cost.

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?

A single five-word phrase, front-loaded with the verb and zero filler. It is efficiently sized, though the brevity borders on under-specification rather than true economy.

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?

Output schema exists so return values need not be explained, and annotations cover safety. But for a tool with one undocumented required-format parameter and a dense sibling namespace, the definition leaves the agent guessing about when this should be called and what the connection_context argument represents.

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%, and the single parameter connection_context (a mctx_v1_ token) is never mentioned in the description. The schema only exposes a regex pattern, so the description had room to explain what the connection context selects and does not. It fails to compensate for the coverage gap.

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 ("Read") and resource ("stored Insights date coverage"), so the agent can grasp it returns the date span of stored Insights data. However, "date coverage" is jargon and the description does nothing to separate it from the many sibling insights_* tools (insights_read_breakdowns, insights_query_overview, etc.). Adequate but underspecified.

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, when-not-to-use, or alternative named. The agent must infer from the name alone that this is a pre-flight/coverage check rather than a data pull. With ~120 siblings including several insights readers, the absence of routing guidance is a real gap.

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