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

Adds substantial behavior beyond the annotations, which only mark it non-read-only/non-destructive/non-open-world. The description discloses a blocking wait of up to 40 seconds, a two-phase link/code approval flow, the persistent side effect that passing device plus Allow signs in the machine for all later sessions, and what is returned when already signed in. That is rich, decision-relevant context.

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?

Front-loaded with the core purpose, then walks the flow in order. It is dense with run-on clauses ('...pick the site and choose Allow, then call sign_in again') but nearly every clause carries procedural information. Minor redundancy in the Signed out / Signed in framing, 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 2-param tool with no output schema, the description covers the flow, the blocking behavior, the return contents (link, code, and which site the session works on), and the persistence side effect. It is essentially complete for calling correctly, with the only real omission being the client parameter's role.

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%, so baseline is 3. The description reinforces device (the hash the plugin's device script prints) and adds the consequence that passing it signs in the machine for every later session, which goes slightly beyond the schema. However it never mentions the client enum parameter at all, so the added value over the schema is modest.

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 concrete verb+resource: 'Sign this session in to Shipfound from the chat.' It is clearly a session-authentication tool, readily distinguishable from sibling reads like access, record_access, and workspace. It stops short of explicitly naming how it differs from those siblings, 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?

Gives clear invocation sequencing: the first call returns a link and code, the agent should have the founder approve, then call sign_in again; subsequent calls block up to 40 seconds. That is strong when/how guidance for a multi-step flow. It does not name alternatives or state when NOT to call it, so not a 5.

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