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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond the annotations: the tool turns the page light green, establishes a session, and can be omitted because other tools connect as well. It does not describe failure modes or what happens with an invalid session code, but the core behavior is transparent.

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?

Three sentences with no wasted words. The most important guidance ('Call this first if...') is front-loaded, and the optionality is stated immediately after. Every sentence earns its place.

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 single-optional-parameter tool with full schema coverage and safety annotations, the description is nearly complete. It explains the purpose, the effect, the session handoff, and when to call it. The only minor gap is that it doesn't describe what happens if an invalid session code is provided, but that is not essential for correct invocation.

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 100%, so the schema already documents the session parameter. The description adds value by explaining where the session comes from ('from an earlier result, or the session code the person gave you') and that omitting it starts a new one. This goes beyond the schema's description.

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 states a specific verb ('Connect'), a specific resource ('the HenryKnows page the person is watching'), and a concrete observable effect ('turns its light green'). It also explains the session handoff purpose, which distinguishes it from the sibling tools ask_henry and search_sources.

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 description gives explicit when-to-use guidance: 'Call this first if the person gave you a session code; otherwise it is optional.' It also names the alternatives (ask_henry and search_sources) and notes that they connect too, so an agent knows when this tool is not required.

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