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

Annotations already declare readOnly, idempotent, non-destructive and openWorld=false, so safety is covered. The description adds real behavioral context not in the schema: rule-based tagging and a 30-day freshness window (plus the 3-day window when tags are empty, which lives in the schema). It does not mention rate limits, caching, or latency.

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?

Two sentences, front-loaded with what the tool returns and its tag taxonomy, then invocation and the 30-day constraint. Dense with zero filler, though the parenthetical "(rule-based)" and the window note could be folded more tightly.

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 6-parameter, all-optional read tool with no output schema, the description covers what is returned and how to scope it. It omits any hint of the response shape (grouping by tag or type, ordering) and how `limit` interacts with the window, which are minor gaps.

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 83%, so the schema already documents lang, tags, since and exclude_ids well. The description reinforces the tags parameter with concrete examples and notes since is optional and the overall data window, but adds little beyond the schema's own parameter text. Baseline 3 is appropriate.

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 names a concrete resource (a developer's stack brief) and enumerates its content types (security notes, breaking changes, model releases, new tools, news), so the agent knows exactly what it returns. It distinguishes itself implicitly from the news-only siblings by tying items to stack tags, but never names latest_news or search_news to draw the line 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?

"Pass the stack tags ... and optionally a since date" gives invocation guidance for this tool but offers no when-to-use versus the sibling news tools (latest_news, search_news, find_tools). Usage is implied by the stack-tag framing rather than stated as a routing rule.

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