session_start

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

With no annotations, the description carries the full burden and does so richly: it discloses what gets initialized, that no solving occurs until session_advance, that the live model stays resident for step/inspect/modify, isolate semantics (private copy, original files and outputs untouched), non-persistence across server restart, and a concurrency cap (KRATOS_MCP_MAX_SESSIONS, default 4).

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 core action and return value, followed by constraints and lifecycle notes. Two dense paragraphs where every sentence adds routing, safety, or lifecycle information relevant to correct invocation.

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?

An output schema exists, so return-value explanation is unnecessary, and the description covers lifecycle, isolation, concurrency, and case-type constraints thoroughly. The only real gap is the undocumented non-isolate parameters, which keeps it from a 5.

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 0% across 6 parameters, so the description must compensate, yet it explains only isolate=True and the implicit case_load behavior. timeout, analysis_type, analysis_class, and parameters_file are entirely undocumented in both schema and prose, leaving most invocation semantics to guesswork.

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 (open an interactive Kratos session), then enumerates precisely what happens: load the case, build the AnalysisStage, run Initialize(), return a session_id and initial state. It explicitly contrasts itself with run_simulation, so an agent can distinguish it from siblings without opening schemas.

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?

Explicitly states the applicable cases (single-stage, serial/OpenMP only) and the exclusions (multi-stage, CoSimulation, FSI, MPI are rejected) with a named alternative (use run_simulation). It also clarifies that nothing is solved until session_advance, giving clear when-to-use boundaries.

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