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

Annotations already declare the safe read-only, idempotent profile, so the description's real contribution is disclosing that the tool returns a link rather than the image itself, requiring a second fetch to actually see the screen. That two-step workflow is exactly the kind of behavior an agent would otherwise miss; link expiry or authorization failure behavior is the remaining gap.

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, no filler, and the actionable follow-up step ('Fetch the returned image') is placed immediately after the statement of what is returned.

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?

For a two-parameter read tool with full safety annotations and no output schema, the description covers what is produced and how to consume it. Only minor gaps remain: link lifetime and how authorization failures surface.

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 50%: 'url' is thoroughly documented in the schema, but 'seconds' has no schema description. The description's 'timestamp' wording maps loosely to 'seconds' but adds no format, precision, or boundary meaning beyond the 0–86400 range already in the schema.

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?

Specific verb ('Get') plus specific resource ('authorized image link') scoped to a timestamp in a playable recording, which clearly separates it from read_recording and read_transcript. It stops short of naming those siblings as alternatives, so differentiation is inferential rather than stated.

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 phrase 'in a playable recording' implies a precondition, and 'Fetch the returned image to inspect the screen' implies when the result is useful, but there is no explicit when-to-use versus read_recording or read_transcript and no guidance on failures or unsupported recordings.

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