katto_list_sources

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so 'Read-only' adds nothing new. However, the description discloses the return content ('each with an example URL'), which matters because there is no output schema and the annotations say nothing about response shape.

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 sentences, front-loaded with the safety/scope statement and ending with the routing decision. The 14-platform enumeration is long but directly supports the tool's stated purpose of confirming URL support, so it largely 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?

For a zero-parameter, read-only list tool with no output schema, the description supplies everything needed: what is returned, that each entry includes an example URL, and how it fits into the clip-creation workflow versus katto_upload_video.

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?

The tool takes no parameters, so the baseline is 4; there is nothing for the description to clarify beyond the schema. No parameter-related ambiguity exists.

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 ('list') and resource ('link sources Katto can clip from'), then enumerates the supported platforms so the agent knows the scope exactly. It is unmistakably distinct from siblings like katto_list_connected_accounts or katto_list_jobs.

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 an explicit when-to-use ('confirm a URL is supported before calling katto_create_clip_job') and an explicit alternative for a different case ('for a local file use katto_upload_video instead'). This is exactly the routing guidance an agent needs.

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