select_model

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the agent knows this mutates non-destructively in an open world. The description adds real context beyond that: the 'idle session' precondition and that changes are acknowledged by WorkBuddy. It omits what happens if the session is busy, whether an existing model selection is replaced, and whether other sessions are affected.

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 short sentences, front-loaded with the primary operation and then the parameter-dependent branches. The parenthetical '(omit model_id)' is slightly awkward but eliminates ambiguity efficiently; no filler sentences.

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-optional-parameter tool with no output schema and no required fields, the description covers the modes of operation adequately. Gaps remain around how the model list is returned and what 'idle' means operationally, which matter because the same tool both reads and mutates.

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 0%, so the description carries the full burden, and it does explain the presence/absence semantics of both parameters precisely (omit model_id = list, omit session_id = new session). It does not indicate what a valid model_id looks like or where to obtain one, leaving a gap on value format.

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 resource (runtime-reported models) and a specific action (select one for a session), and it resolves the ambiguity created by the tool name by explaining that omitting model_id turns it into a list operation. It does not distinguish this tool from siblings such as select_mcp_or_skills, which likely also performs selection, so it stops short of a 5.

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 concrete trigger conditions for parameter omission (omit model_id to list, omit session_id to create a new managed session) and notes selection applies to an 'idle session'. However, it never names an alternative tool or says when not to use this one versus select_mcp_or_skills or send_message, so usage is only implied.

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