ModelFit Recommend

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

Annotations only declare readOnlyHint=true; the description meaningfully extends that with 'No model is called and nothing is stored' and 'constraints that fail closed,' which tells the agent the failure mode is hard failure rather than best-effort. It also discloses an environment prerequisite (agenticlens>=0.9.0), which is real behavioral context beyond the annotation.

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, each carrying distinct load: purpose+constraints, return payload, side-effect/version facts. Front-loaded with the core action and nothing is repeated across sentences.

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 does the work of describing the return payload (per-category recommendations, confidence, fallbacks, savings, quality risks, full report, task-level matrix), which is thorough. The only missing piece is any hint about session_id/shared-state behavior, which the schema mentions as read/write.

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 config, reports, session_id and variant_metadata; baseline is 3. The description echoes the constraint categories (which live in config) and the reference variant concept, but adds no new semantics such as accepted report format or config keys.

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?

Specific verb+resource with the constraint space enumerated; distinguishable from execution siblings, though it never names an alternative sibling explicitly.

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 implies when it applies by requiring 'supplied AgenticLens experiment reports' as input, which narrows usage context. But there is no explicit when-to-use/when-not guidance and no routing against lens.routing_decide or lens.compare_runs, so selection still requires inference.

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