switch_instance

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

With no annotations, the description carries the full burden and does well: it discloses that only this session's bridge is re-pinned, that other sessions are untouched unless all_sessions=true, and that all_sessions writes the registry default and bumps active_epoch. It omits error behavior (e.g. unknown instance name) and any permission prerequisites.

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?

Three tight sentences, front-loaded with the dual behavior and the listing mode before the switching mode. Minimal waste, though the instance/all_sessions wording partly duplicates the schema descriptions.

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?

No output schema exists, and the description does state that listing returns instances with their status, which covers the main return expectation. Combined with the mutation-scope disclosure, it is nearly complete for a 2-param tool, missing only failure modes.

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%, so the schema already documents both parameters including the toe-basename format and the all_sessions default. The description restates the same semantics without adding format, validation, or edge-case detail, 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 a specific verb (switch) and resource (this session's TouchDesigner instance) and explicitly covers the dual mode (switch vs list). An agent can distinguish it from siblings like get_td_status, launch_td, and restart_td without opening any schema.

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?

It gives clear conditional usage: omit 'instance' to list, supply a name to re-pin. That covers the when-to-use decision for both modes, but it does not name an alternative tool or state when a different sibling (e.g. get_td_status) would be preferable.

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