web_watch

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

With no annotations, the description carries the full burden and does so well: it discloses that a snapshot is saved per successful fetch, that failures (blocking/timeout/login wall) do not overwrite the old snapshot, that reset rebuilds the baseline and returns first_seen=true, and how caching interacts with bypass_cache. Missing are concurrency/rate-limit expectations and what happens on the very first call for a URL, but the stateful semantics are unusually well surfaced.

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 and statefulness are front-loaded, then failure/snapshot behavior, then an Args block that maps one-to-one onto the schema. The Args block is long but each line carries operational meaning; there is no filler or repeated information.

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 7-parameter stateful tool with no annotations, the definition covers persistence model, failure handling, first-call/baseline behavior, caching, session coupling, and proxy/deadline semantics, and an output schema exists so return shape need not be restated. An agent has enough to call this correctly on the first attempt.

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 0%, so the description must compensate, and it documents all seven parameters in ways the schema cannot: reset returns first_seen=true, bypass_cache defaults to true and lets CACHE_TTL content be reused, session must match the name used at login, deadline_ms is a total call budget, and proxy falls back to the pool or global config. This adds genuine meaning beyond types and defaults.

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: detect changes in a page (or a block within it) since the last call, with snapshot-based diffing. This is clearly a stateful watch tool rather than a plain fetch, so an agent can distinguish it from web_fetch/web_crawl in practice. It never names those alternatives explicitly, which keeps it just short of a 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 a concrete usage scenario ("每天看一眼这个页面有没有新内容") and the conditions that change the behavior for reset and bypass_cache. It also ties session usage to the login tool ("需与 login 时使用的会话名一致"), which is a real routing constraint. No explicit when-not-to-use or alternative-tool guidance is given.

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