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

Annotations only say readOnlyHint=false and idempotentHint=false; the description adds substantial context beyond that: daily comparison schedule, per-owner slot limits, 402 on overflow, pre-payment rejection of unsupported sources, and e-mail notification of changes. It omits how the watch is later removed or how the agent retrieves the diffs (presumably watch_alerts), which keeps it short of a 5.

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 text is a run-on series of fragments separated by semicolons and periods, and several clauses are policy disclaimers rather than tool guidance — notably "Catalog signals and change notices are not a security audit…" and "Local hooks do not freeze remote MCP code." The lead clause is front-loaded correctly, but the body is dense and unscannable.

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 one required parameter and no output schema, the description covers scheduling, quota, failure codes and notification delivery, which is most of what an agent needs. It still leaves gaps on the lifecycle side — how to read the resulting changes and how to stop watching — and pads the remaining space with security caveats instead of those operational details.

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 listing_id is fully documented in the schema, including the mcp_/skl_ prefixes. The description's mention of "remote MCP or supported SKILL.md" loosely maps to those prefixes but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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?

"Watch a remote MCP or supported SKILL.md" gives a specific verb plus the two resource types it accepts, which separates it from unwatch_tool and list_watched_tools. It is clear what the tool does, though the purpose is stated in the first clause and then buried under policy caveats rather than developed.

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?

Usage is implied by the quota and pricing notes (3 free slots, 402 for more, unsupported sources rejected before payment), so an agent can infer the conditions under which a call will fail. But there is no explicit "use this when…" statement and no routing to siblings such as unwatch_tool or list_watched_tools to check existing watches.

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