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

With no annotations provided, the description carries the burden of behavioral disclosure. It explains that the output is markdown, outlines the sections included, and notes the requirement for an exact slug to succeed. This gives the agent a clear expectation of what the call returns and what input is needed, though it does not mention error handling for invalid slugs or any authentication/rate-limit considerations.

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 two sentences with no filler. It front-loads the primary purpose and output format, then immediately gives usage guidance and a prerequisite. Every sentence contributes essential information for selecting and calling the tool correctly.

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?

The tool is a simple getter with two documented parameters and no output schema, so the description provides more than enough context: what it does, what the markdown includes, when to use it, and how to obtain the required slug. There is no missing information that would prevent an agent from invoking it correctly.

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 input schema already thoroughly documents both parameters: slug is described with examples and guidance to get it from search/list results, and context has a detailed multi-sentence explanation. The tool description reinforces the slug requirement but adds no meaningful semantic information beyond what the schema already provides.

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 ('Explain') and resource ('a trading concept') and details the exact content returned: the Library's full write-up as markdown, including definition, formula, how traders read it, and indicator implementations. It clearly distinguishes itself from sibling get tools like library_get_family or library_get_source_code by focusing on the conceptual write-up.

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 explicitly says to use this for 'what is X / how does X work' questions, providing clear context for when to invoke it. It also directs agents to find the required slug via library_search or library_list_concepts, naming the relevant alternatives for satisfying the prerequisite. It does not explicitly state when not to use sibling get tools, but the use case is specific enough.

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