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

Annotations only declare readOnlyHint, and the description adds useful context beyond that: the exact response envelope keys and the fact that the call is team-scoped, plus the alternative teamId resolution noted in the schema. It doesn't mention permissions or error behavior, but the read-only safety profile is already covered by annotations.

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 action and resource, and every clause adds information (response shape, `from` semantics, team scope). The embedded JSON shape makes it dense but not wasteful.

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?

With 100% schema coverage and no output schema, the description usefully compensates by outlining the return object and noting team scoping. An agent has enough to invoke it correctly; only explicit sibling routing is missing.

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 all three parameters are already documented in the schema (including the teamId default and the from timestamp format). The description's note that `from` sets the window start for rendered shifts adds only marginal nuance over the schema. Baseline 3 applies when the schema does the heavy lifting.

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 ("Get one on-call schedule by id") and even sketches the returned object shape. The "one ... by id" framing clearly separates it from the sibling spike_list_on_calls.

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?

The "by id" phrasing conveys the single-item retrieval context versus the list sibling, and it notes the request is team-scoped. However, it never explicitly names the alternative (spike_list_on_calls / spike_who_is_on_call_next) or states when to prefer this over them.

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