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

With no annotations, the description carries the full burden and excels: it explains the verdict/confidence distinction ('reported' is authoritative vs 'inferred' is a guess), instructs how to phrase it ('say so rather than stating it flatly'), warns that stillRunning:true means in-progress and must be reported as such, and discloses the access limitation that another user's session is indistinguishable from a nonexistent one.

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?

Longer than average, yet every sentence earns its place: purpose is front-loaded, followed by trigger conditions, then the behavioral nuances (confidence, stillRunning, access limits) that an agent must know to report correctly. No filler or repetition of schema content.

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 tool with no output schema and no annotations, the description is complete: it enumerates the return contents, defines the semantics of ambiguous values, and covers edge cases (in-progress runs, other users' sessions). Nothing an agent needs to call 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?

Schema coverage is 100% — sessionId is documented in the schema with the same /automation?session_id=... source. The description adds marginal context (the agent should recognize a pasted session id as the invocation trigger), but the schema already does the heavy lifting, 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?

States a specific verb and resource — 'Read one finished automation run' — and enumerates the exact data returned (verdict, test, device/browser, capabilities, duration, video/snapshot existence). The singular-scope wording distinguishes it from siblings like automation_sessions_list (plural listing) and automation_session_step (a single step).

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 explicit entry conditions: 'START HERE when the user pastes a session id or an /automation?session_id=... link and asks what happened, why it failed, or how it went.' This clearly tells an agent when to reach for this tool, but it does not name alternatives or state when-not-to-use, so it stops 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.