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

The description is otherwise unusually rich (daily schedule, source quota, account e-mail notifications, 30-day non-renewing slots, Claude Code allowlist exclusion), but it explicitly claims 'Watching again is a no-op,' i.e., repeated identical calls produce no further effect, while the annotations declare idempotentHint=false. That is a direct contradiction of a declared annotation, which the rubric scores as 1.

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?

It is front-loaded (core action first, then constraints) and compact overall. However, several compressed fragments such as 'account e-mail for changes' and 'Skills cover text and review signals, not execution' read as telegraphic rather than cleanly structured, keeping it just below top marks.

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 subscription tool with no output schema, the description covers the operational facts an agent needs: prerequisites, schedules, quota, expiry, and allowlist behavior. It says nothing about what a successful watch returns or how to manage the resulting subscription, but that gap is minor given the sibling tools available.

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 100%: the single listing_id parameter is fully documented in the schema (format `mcp_…`/`skl_…`, sourced from `/api/listings`). The description adds no additional syntax, constraints, or examples beyond that, so the 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?

The opening sentence names a concrete action (watch) and its two supported resources (a remote MCP server or a supported SKILL.md), so the agent immediately knows what the tool operates on. It does not explicitly differentiate itself from siblings such as unwatch_tool or list_watched_tools, but the verb is distinct enough to disambiguate.

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?

It gives real selection conditions: 'Choose a live remote MCP or a skill with a supported public raw.githubusercontent.com SKILL.md, after skill collection is enabled,' plus schedule/quota context. It stops short of naming alternatives (e.g., unwatch_tool) or stating explicit when-not-to-use cases, so it is context-rich but not fully routing.

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