follow_up

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

With no annotations, the description carries the transparency burden. It discloses a key behavioral trait: the full prior context is preserved server-side, so the agent should not resend context. This explains the stateful nature of the tool. It could further mention error behaviors or authentication, but the most critical behavioral differentiator is disclosed.

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?

The description is two sentences, front-loaded with purpose, and follows with usage guidance. Every clause earns its place: the session_id source, the timing ('follow-up'), the rationale ('context already on agy's side'), and the behavioral instruction ('don't resend anything'). No filler 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?

For a relatively simple tool with two required parameters and full schema coverage, the description covers purpose, usage context, session_id provenance, and the stateful behavior. No output schema exists, so no return-value explanation is required. The tool's role among siblings is clearly established, making this contextually complete.

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%, so the baseline is 3. The description adds meaningful value by clarifying that session_id is returned by every other tool, which aids the agent in locating the value, and reinforces that question is the only new input. This goes beyond the schema's parameter descriptions, so a 4 is warranted.

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 opens with a specific verb and resource: 'Continue a previous Antigravity session by session_id.' It also explicitly distinguishes itself from siblings by noting session_id is 'returned by every other tool' and that this is for 'follow-up questions about a prior delegation,' clearly differentiating it from delegate, analyze_files, etc.

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 an explicit usage directive: 'USE THIS for follow-up questions about a prior delegation — the full prior context is already on agy's side, so you don't resend anything.' This tells the agent exactly when to choose this tool and what not to do, serving as a clear alternative to other delegation tools.

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