morning_brief

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

The description adds valuable behavioral context beyond the annotations: it specifies the output is a single markdown brief, includes today's weather and exactly 5 HN stories, and notes 'No API keys needed.' This is useful, and it does not contradict the readOnly/openWorld hints.

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, with the WHEN TO USE trigger front-loaded. Every sentence conveys essential information: when to use, what it returns, and a notable constraint (no API keys). No wasted words.

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 simple tool with one optional parameter and no output schema, the description is largely complete. It covers the trigger, the content of the brief, and a key operational detail. It could mention the exact format of the markdown (e.g., headings) or pagination, but for this scope it is sufficient.

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?

The schema already provides 100% coverage for the one parameter (city) with a clear description. The tool description only repeats this by saying 'today's weather for a city,' adding no new semantic information. 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 clearly states the tool returns a markdown brief with today's weather for a city plus the top 5 Hacker News stories. This specific verb+resource combination distinguishes it from the sibling hn_top, which likely focuses solely on HN stories.

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?

The description opens with an explicit WHEN TO USE condition: 'the user asks for a morning briefing or daily summary.' It provides clear context, though it does not explicitly mention when NOT to use it (e.g., if only HN stories are requested, hn_top might be more appropriate).

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