Show how to attach to a session

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description usefully adds that it only returns a command string rather than executing anything, plus the terminal environment requirement. It stops short of saying what happens for an unknown or dead session, which is the remaining behavioral gap.

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 return value and followed by environment guidance. No filler and nothing an agent must read past to act.

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 one-parameter read-only helper with no output schema, the description tells the agent what comes back (a tmux attach command) and who should call it instead. Nothing needed to invoke it correctly is missing.

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 single 'session' parameter is fully documented in the schema at 100% coverage, so the baseline applies. The description's phrase 'for a session' adds no format, naming convention, or lookup behavior beyond what the schema already states.

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 and resource — returns the tmux attach command for a named session — and immediately contrasts it with terminal_read/terminal_write, so an agent can separate it from its closest siblings 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?

Explicitly names the condition for use (running from a Termux terminal for direct human interaction) and the condition against it (external Android apps should keep using terminal_read/terminal_write). That is a concrete when/when-not plus a named alternative.

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