ck_set_session

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

Annotations only declare readOnlyHint=false, so the description must carry the burden. It usefully frames the input as a live auth credential and explains how to obtain it, but does not disclose mutation side effects such as whether an existing session is overwritten, how long it persists, or any security handling of the stored cookie.

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?

Purpose is front-loaded in the first sentence, and the second sentence earns its length by telling the user how to get the cookie and offering an automated alternative. Slightly long second sentence but no filler.

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?

For a one-parameter, no-output-schema tool with minimal annotations, the description covers purpose, input provenance, and an alternative onboarding route. It leaves only the store/overwrite semantics and credential lifecycle unaddressed.

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 coverage is 100% and the single parameter is already documented, so the baseline is 3. The description goes beyond the schema by giving the exact provenance and extraction procedure (DevTools → Network → Request Headers → cookie), adding real meaning for how to produce a valid value.

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 ('Store a Credit Karma session') plus the outcome it enables ('automatic token refresh'). It is clearly distinguishable from siblings like ck_forget_session and the ck_* data-retrieval tools.

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?

Explains the onboarding context and explicitly names an alternative path ('the easier onboarding path is to install the ContextMint Bridge extension'), which routes the agent/user appropriately. It does not state when this tool is unnecessary (e.g., session already stored), so it stops short of full when/when-not guidance.

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