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

Annotations already declare readOnlyHint=true and destructiveHint=false; the description reinforces this with 'Read-only, 0 credits' and adds critical behavioral nuances: the 'captured' vs 'backfilled' distinction explains how data was recorded, and the warning that a dash for engagement is NOT zero engagement prevents misinterpretation. These details go beyond the structured hints, though it could further mention pagination/rate limits.

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?

The description is reasonably efficient: the main action is front-loaded, and the subsequent sentences explain data provenance and the dash nuance, both essential. However, the phrase 'the memory that makes "which hook worked?" answerable at all' is rhetorical and could be trimmed without losing selection-relevant information. Still, each 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?

Given that schema covers parameters and annotations cover read-only/non-destructive behavior, the description fills all remaining gaps for correct use and interpretation: it lists the returned fields, explains how data was recorded (captured/backfilled), clarifies ambiguous engagement values, and states the cost/credit implications. No output schema exists, but the listed fields effectively serve as an output contract, making this complete.

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%: both limit (with default and max, plus ordering) and channel (with the allowed list) are fully documented. The description mentions 'all nine channels' which aligns with the channel parameter and implies an aggregating behavior, but it adds no new meaning about parameter usage or constraints beyond what the schema already provides.

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?

The description states 'List every post Hermoso has recorded publishing for this brand' with a clear verb and resource, and enumerates the fields returned (channel, permalink, caption, etc.), making its purpose unambiguous. It differentiates from platform-specific list tools by framing it as the unified brand publishing history across all nine channels, though it does not explicitly name a sibling tool to contrast with.

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?

The description implies when to use it by emphasizing it is the brand's own publishing history and the 'memory' for answering hook performance, and notes it is read-only and cost-free. However, it does not explicitly state when not to use it or name alternatives like list_meta_posts or list_tiktok_videos, leaving the agent to infer the scope boundary from context.

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