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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the write/safe-mutation profile is covered. The description adds one genuine behavioral fact ('Deletes are not supported', i.e. no delete counterpart to this create), but says nothing about required-field handling, side effects on linked setups/logs, or auth needs for a 22-parameter mutation.

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 short, front-loaded sentences with no filler, so it is not bloated. However, this brevity is under-specification rather than disciplined concision given the tool's 22-parameter surface, so it lands at a minimum-viable 3.

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 values need not be explained. But with 22 parameters at 5% coverage, two enums, and no indication of how the many optional session attributes are used, the description is materially incomplete for a tool of this complexity.

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 only 5% (essentially just sessionDate), so the description carries the full burden for 22 parameters, including two enum fields and seventeen undocumented strings. It mentions no parameter at all, adding zero meaning beyond the schema.

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 and resource ('Saves a new TuneWorks driving session'), which is enough to place it against update_session, copy_session, and archive_session. It is clear but does not explicitly name which sibling to prefer, so it stops short of a 5.

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?

There is no when-to-use guidance, no preconditions, and no pointer to alternatives such as update_session or copy_session. The closing note about deletion is a scope remark, not usage direction, so the agent is left to infer everything.

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