Open multiplexing master

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

Annotations only say the call is not read-only, is open-world and not destructive, so the description carries most of the burden and it does add real operational context: the open is best-effort, it may return an interactive command for a real terminal, Duo must be approved once, and the socket is then reused by the agent. It still omits what a best-effort failure looks like or whether a stale socket must be cleared first.

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?

A single front-loaded sentence covering the primary behavior and the notable Duo exception, with essentially no filler. Slightly dense with the parenthetical, but every clause carries information.

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 no output schema, the description should explain what the tool yields and the failure path; it names the Duo return value but says nothing about the non-Duo return, socket lifetime, or teardown. Adequate for a setup-style tool, but a caller still has to guess at the alias parameter and the failure semantics.

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 50% — only 'profile' is documented, while 'alias' carries nothing in either the schema or the description. The description never mentions alias or explains that it is an SSH host alias, so it does not compensate for the coverage gap on a parameter the caller must supply correctly.

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 ('open') and resource ('ControlMaster session'), making the multiplexing purpose clear. It does not, however, differentiate itself from close siblings like ris_check_ssh_master or ris_repair_stale_socket, which an agent browsing the list could confuse it with.

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 phrase 'best-effort open' and the Duo workflow imply a pre-flight/setup role, and the Duo branch tells the agent what to do on hosts requiring interactive auth. But there is no explicit statement of when to call this versus ris_check_ssh_master, nor any stated prerequisite or follow-up ordering.

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