reason

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

Despite no annotations, the description discloses important behavioral traits: mode switching based on 'sources', that 'reasoning_depth' is ignored in sources-aware mode, and the fixed prompt nature in that mode. It also mentions the per-request API key override. Could be improved by explicitly stating it is a read-only operation with no side effects.

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?

Well-structured with clear mode breakdowns, using bullet-like formatting for readability. Every sentence provides necessary information, 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?

Given the presence of an output schema, the description doesn't need to detail return values. It covers the two modes, parameter behavior, and alternative tools. Missing aspects like error handling or rate limiting, but overall sufficient for the tool's complexity.

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%, baseline 3, but the description adds significant context: explains the two modes and how parameters behave differently in each (e.g., 'context' and 'reasoning_depth' only in no-sources mode, 'sources' switches modes). This greatly enriches the agent's understanding.

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 defines the tool's purpose: deep reasoning with chain-of-thought analysis, with two distinct modes. It distinguishes itself from the sibling tool 'synthesize' by noting that for style variants over pre-gathered sources, one should call 'synthesize' directly.

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?

Explicitly states when to use each mode: no-sources mode for problems requiring reasoning without external evidence, sources-aware mode when sources are provided. Also provides an alternative: 'For style variants over pre-gathered sources, call synthesize directly.'

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