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

Annotations already declare readOnly, idempotent, and closed-world, so the safety profile is covered. The description adds genuine value by disclosing the returned payload fields and the cache-dependency condition. It stops short of saying whether a cache miss yields an error or empty result, which would complete the picture.

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?

Two short sentences: the first front-loads the returned content and source, the second is a direct call to action. No filler, no redundancy.

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 burden of describing the return value and does so by enumerating transcript, summary, key points, and chapters. The only gap is undefined behavior on a cache miss, which is minor for a single-parameter read tool.

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 the single 'url' parameter is fully documented in the schema, including the accepted sources (YouTube, Apple Podcasts, Spotify). The description's 'Give the video or episode URL' merely restates that, so the baseline 3 applies.

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 names the resource precisely (transcript, summary, key points, chapters) and the source (YouTube video or podcast episode), so an agent knows exactly what it retrieves. No siblings exist to differentiate from, and the tool name matches the description without tautology.

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 clause 'if blumify.io already has it' implicitly signals this only works for already-processed content, which is useful context. However, it gives no guidance on what to do for uncached content, no prerequisites, and no alternatives — usage is only implied.

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