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

Annotations already declare readOnlyHint/idempotentHint, but the description adds substantial beyond-schema behavior: it never regenerates, the scope rules (50 top-view posts, last 365 days, minimum 10, images/carousels excluded), the exact freshness triggers (language, format, count change of >=5), and a caveat that diagnoses are AI hypotheses not measured retention.

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 read verb and returned fields, and the scope/freshness specifics are ordered sensibly. It is dense but mostly earns its place, with a minor redundancy between 'Read-only: never regenerates' and 'Does not regenerate insights.'

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?

With no output schema, the description carries the full burden and does so well: it documents return fields, the freshness state machine (missing/insufficient_data/stale/available plus reasons and canGenerate), scope limits, and interpretation caveats. Nothing material for correct invocation 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 0% and the single optional brandId parameter is never mentioned in the description. The text richly explains the data scope, which partially compensates, but adds no meaning for the one parameter the agent must supply.

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') on a specific resource ('saved homepage insights') and enumerates the fields it surfaces (generatedAt, currentVideoCount, scope, freshness). The 'never regenerates' clause implicitly separates it from generate_insights, letting an agent tell the two apart 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?

It establishes clear context for when this applies – reading already-saved insights rather than producing them – and the 'never regenerates' framing points away from the generative sibling. However, it never names an alternative (e.g. generate_insights) or states an explicit exclusion, so routing is inferred rather than prescribed.

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