Galaxy Brain

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It describes the core behavior (starting a thinking session) and mentions the return value (session_id), but doesn't disclose important behavioral traits like whether this is a read-only or mutating operation, what happens if a session already exists, or any rate limits or authentication requirements. The description adds basic context but leaves significant behavioral aspects unspecified.

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?

The description is perfectly concise with just two sentences that each earn their place: the first explains the tool's purpose, and the second explains the return value and its significance. It's front-loaded with the core functionality and wastes no words on unnecessary details.

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 that this is a tool with 2 parameters, no annotations, and no output schema, the description provides adequate but minimal context. It explains what the tool does and what it returns, but doesn't address important contextual aspects like error conditions, session lifecycle management, or how this fits into the broader thinking workflow beyond mentioning other thinking tools. For a session-initialization tool, more context about session management would be helpful.

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%, so the schema already fully documents both parameters. The description doesn't add any parameter-specific information beyond what's in the schema - it mentions the general purpose ('to reason through a problem') but doesn't provide additional context about parameter usage, constraints, or relationships. This meets the baseline expectation when schema coverage is complete.

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's purpose with specific verbs ('start a new thinking session') and resource ('to reason through a problem step by step'), and distinguishes it from siblings by mentioning 'session_id to use with other thinking tools' which implies it's an initialization tool in a thinking workflow. It doesn't just restate the name but explains what the tool actually does.

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 provides clear context about when to use this tool ('to reason through a problem step by step') and implicitly distinguishes it from alternatives by mentioning the session_id for use with other thinking tools, suggesting this is the entry point for a thinking process. However, it doesn't explicitly state when NOT to use it or name specific alternative tools for different scenarios.

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