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

Annotations only carry the generic flag set (not read-only, not idempotent, not destructive). The description adds genuinely useful behavior: expectDeviceName mismatch opens nothing (a silent no-op guard), startup is metered and counted as one project read, and omitting startup opens only the session.

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?

Front-loaded with the use condition and the critical expectDeviceName guard, then returns, then the startup cost tradeoff. Dense and information-bearing, though a few clauses (return enumeration plus cost note) could be tightened.

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?

No output schema exists, and the description compensates by naming the return shape (authenticated account, device ID/name, session envelope, optional startup context). Prerequisites, the failure mode, and the metering cost are all covered for this 5-parameter nested tool.

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?

With 100% schema coverage the baseline is 3, but the description adds real meaning beyond the schema: it explains expectDeviceName is the PC name the user gave and that a mismatch prevents opening, and characterizes what startup returns and its cost. It does not fully restate required-param prerequisites, keeping it below 5.

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 ('opening a session on the explicitly selected device/workspace') and scopes it precisely enough to separate it from execution_session_close and the discovery siblings. An agent can tell what this does without opening the 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?

Gives clear context: use it for the explicitly selected device/workspace, and 'Discover workspace IDs first only when unknown' conditions the discovery path. The prerequisite routing to project_target_resolve is left to the schema rather than the description, and there is no explicit when-not statement, so it falls short of a 5.

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