Compare sessions

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered; the description adds the non-obvious operational constraint that both sessions must be terminated first, which is genuine context beyond annotations. It stops short of saying what happens if the precondition is unmet or how large diffs are bounded.

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?

Two sentences, zero filler: the action and return contents come first, the gating precondition second. Every clause 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?

With no output schema, the description carries the return-value burden and does so by enumerating the comparison categories. Combined with the stopped-session precondition and fully documented params, an agent knows enough to call it, though it lacks detail on ordering or result size.

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% and both parameters carry clear role descriptions ('Session being evaluated (newer / candidate)' vs 'Reference session'). The description's phrase 'against a baseline session' mirrors the schema without adding format or constraint detail, so the baseline 3 is appropriate.

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?

Names a specific verb (diff/compare) and resource (sessions) and specifies the output shape: added/removed/changed requests, latency deltas, finding drift. No sibling tool performs session comparison, so an agent can route here unambiguously against get_session, list_sessions, or replay_session.

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 supplies a precondition ('Both sessions must be stopped') that implies usage, but it does not state when to reach for this vs alternatives like replay_session or get_session, nor any exclusions. Usage is inferable but not explicitly guided.

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