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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds value by ruling out side effects ('does not ... change a recording') and framing content scope; the schema further warns that recording content is untrusted source material.

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 compact sentences: the first front-loads the resource and the enumerated return fields, the second delivers the disambiguation as a single negative clause. No filler.

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 one fully documented parameter and annotations covering read-only/idempotent behavior, the description covers what an agent needs to select and call it correctly. It could go further by naming the sibling to use for transcripts or change lists.

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% and the parameter already documents the /v/ share URL format, the 'Copy for AI' fallback for protected recordings, and the untrusted-content caveat. The description only echoes 'user-supplied', adding no syntax or format detail beyond the schema, so 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 (read) and resource (a Tellscreen recording) and enumerates exactly what is returned: title, readiness, summary, chapters and resources. The negative clause 'does not list a library or change a recording' separates it from listing and mutation siblings such as read_change_list.

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 makes the usage boundary clear by stating what this tool does not do, which implicitly routes the agent to a listing or mutation tool for those cases. It stops short of naming the sibling tools (read_transcript, read_change_list) or giving explicit when-to-use conditions.

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