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

Annotations already declare readOnly=true, idempotent=true, destructive=false, so the safety profile is covered. The description adds meaningful behavior beyond that: it enumerates the returned content (link, title, length, transcript) and discloses the negative case ('when none exists it says so and links the page where one can be made'), which is genuinely useful failure-path context.

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 purpose is front-loaded and each clause carries information (what it returns, when to use it, its read-only nature, the no-video fallback). It is a dense single paragraph that runs slightly long, but there is no filler sentence to cut.

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?

There is no output schema, so the description carries the return-value burden and does so by naming the link, title, length and transcript. Combined with the explicit negative case and the covered safety annotations, an agent has everything needed to call this correctly.

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% and the single 'repository' parameter already documents both the owner/repo form and accepted github.com URLs. The description adds no format or syntax detail beyond the schema, 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?

States a specific verb ('Get'), a specific resource ('GitDiagram's narrated explainer video of a public GitHub repository'), and the conditional nature of the result ('if one has been made'). It is clearly distinguishable from the diagram-related siblings find_repository_diagrams and get_repository_diagram.

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?

Gives explicit when-to-use triggers: the user wants a video, something to watch or share 'instead of read', or a spoken-style summary. The 'instead of read' phrasing implicitly routes away from the diagram siblings, but it never names them, so the alternative selection isn't fully spelled out.

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