Attach to Terminal Session

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

Annotations already declare a non-destructive, non-idempotent mutation; the description adds real value by scoping the side effects (no lease taken, no terminal bytes written). It does not address what a repeat call does given idempotentHint=false, nor any auth prerequisites, so it stops short of fully covering the mutation profile.

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 sentence that front-loads the action and immediately qualifies it with the two things it deliberately does not do. No padding or redundancy.

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 an output schema available, return values need not be explained, and the description supplies the critical side-effect boundary for a non-destructive mutation. The remaining gap is whether attachment is live versus recorded-only and what repeated non-idempotent calls yield.

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 100%, with both session_id and the optional actor label documented in the schema itself. The description adds no format, default, or resolution behavior (e.g., what 'short reference' resolves against) beyond what the schema already states, so 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 and resource: recording a client attachment on the Session event stream. The negations ('without acquiring a lease or writing terminal bytes') separate it from terminal_acquire_lease and terminal_write. It falls short of 5 because it never resolves whether a live attachment is actually established or only a record is written.

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 'without acquiring a lease or writing terminal bytes' clause implies when this tool is preferable to lease-based siblings, but no sibling is named and no explicit when-to-use or when-not-to-use condition is given. The agent must infer that terminal_acquire_lease is the alternative path.

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