Official API read

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

Annotations already declare readOnly/openWorld/non-destructive, and the description adds substantial context beyond them: keys live in YOUTUBE_API_KEY/BRAVE_SEARCH_API_KEY and travel in headers, never in receipts; one honest User-Agent with per-host pacing and backoff on 429/503; no login, no cookies; returns JSON plus a receipt. This is rich operational detail consistent with the 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 "Use when..." trigger, followed by tight sentences covering supported channels, auth, network behavior, and return shape. Every sentence carries information, though the dense multi-clause sentence about channel/auth splits is slightly crammed.

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 3-param, 7-channel read tool with no output schema, the description covers auth requirements, rate-limit/backoff behavior, and that it returns JSON plus a receipt. It leaves the meaning of the receipt and per-channel operation semantics unexplained, but the essentials for correct invocation are present.

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 sits at 67%, and the schema already documents op (with examples like top, item, repo, search), params (with an example), and the channel enum. The description restates the channel list but adds no parameter syntax, required-combination, or per-channel op guidance beyond the schema, so the baseline of 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 description states a specific verb and resource (one operation from an official API) and enumerates the exact channels supported (hackernews, github, v2ex, wikipedia, arxiv, youtube, brave). This implicitly differentiates it from siblings like telos.x.api and telos.reddit.listing, which are covered by the excluded channels, but no sibling is named explicitly.

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?

"Use when an agent needs one operation from an official API" gives a clear activation context, and the auth split (zero-auth vs user-key channels) tells the agent which channels require setup. It does not name alternatives or state when NOT to use this tool, so it stops short of full routing guidance.

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