ensemble_open

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

No annotations are present, so the description carries the burden. It does add useful context: the session is writable by several agents and the tool initializes musical parameters. However, it doesn't disclose what happens when reopening an existing session (e.g., overwriting settings), permissions, or return behavior, leaving gaps.

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 description is two sentences, front-loaded with the core action, and every word earns its place. It is concise without being under-specified.

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?

Given the tool's complexity (9 parameters) and lack of annotations and output schema, the description covers the essential purpose and shared-session context. However, it omits other parameters (though schema covers them) and doesn't mention return values or relationships with sibling tools, reducing completeness.

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?

Input schema coverage is 100%, so the baseline is 3. The description mentions key, tempo, metre, and form, which map to existing schema properties, but adds no additional semantic meaning beyond what the schema already provides.

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 clearly states the tool opens or reopens a shared session that multiple agents can write to, and that it sets session-wide key, tempo, metre, and form. This specific verb+resource phrasing distinguishes it from siblings like ensemble_join or ensemble_write_part.

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 conveys when to use it: to start a new shared session or reopen an existing one. It doesn't explicitly name alternatives or exclusions, but the context is clear enough for an agent to choose it over sibling tools.

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