Update session data

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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=true, so the write/destructive profile is covered. The description's 'Overwrite ... send the fields to change' is ambiguous about whether omitted keys are preserved or wiped, which is exactly the behavioral detail that would add value here. It adds the key-naming convention but little else.

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 sentences with no filler; the action and its purpose are front-loaded, and the key-naming hint follows as supporting detail.

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?

The destructive nature is carried by annotations and the key-naming convention is explained, so an agent can invoke it correctly. The one residual gap is the merge-vs-full-overwrite semantics of the 'data' object and the absence of any return-value description, though no output schema exists to lean on.

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 baseline is 3, but the description goes beyond the schema by explaining that the free-form 'data' object's keys must match those returned by sessions_get's data. That is meaningful guidance for an arbitrary-key map with additionalProperties.

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 ('Overwrite') and resource ('session data values') and gives a concrete example use case (correcting a counter on overlays). It implicitly separates itself from sessions_get by naming it as the source of key names, though it does not explicitly distinguish itself from sessions_reset or sessions_update_settings.

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?

Provides a clear motivating scenario ('to correct a counter shown on overlays') and directs the agent to sessions_get for the correct key names. It stops short of stating when not to use it (e.g. versus sessions_reset or sessions_update_settings).

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