session_profile_set

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

With no annotations, the description carries the full burden, and it does add real behavior: fingerprint is auto-generated on first launch if unset, fingerprint takes precedence over launch_options in the merge chain, and proxy_ref overrides launch_options proxy_ref. It still omits side-effect traits such as whether an unknown profile name silently creates one, persistence durability, and permission/auth requirements, so it is only partially transparent.

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?

The purpose is front-loaded in the first clause and the remaining sentences are dense with usable semantics rather than filler. It is long, but nearly every sentence carries new information about a parameter, so length is justified.

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 output schema exists, so return values need no explanation, and the highest-risk parameters (fingerprint, launch_options, proxy_ref, warming_status) are explained. However, for an upsert mutation with zero annotation coverage, missing coverage of the required profile param and account_aliases leaves the definition incomplete.

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 7 params, so the description must compensate. It documents launch_options (with a full key list), fingerprint, proxy_ref and warming_status semantics well, but leaves profile (the only required param), description and account_aliases entirely undocumented — a meaningful gap for the single required input.

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?

Opens with a specific verb+resource: 'Create or update a saved profile', which is an upsert clearly distinct from sibling session_profile_get, session_profile_list and session_profile_delete. It stops short of naming a sibling to route against, so it lands at 4 rather than 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?

No statement of when to prefer this tool over alternatives such as session_profile_regenerate_fingerprint or session_set_fingerprint, and no prerequisites (e.g. whether an active session or existing profile is required). The precedence notes about fingerprint vs launch_options fingerprint fields are about field merging, not tool selection.

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