read_lesson

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

With no annotations, the description must disclose behavior, and it does mention the return format ('readable markdown-ish text with headings and code blocks'). However, it omits error behavior, such as what happens if the URL is invalid or not found, leaving a gap in transparency.

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, front-loaded with the main purpose, and contains no filler. Every word contributes to understanding the tool's function and output.

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 read-only tool with one parameter and no output schema, the description covers the core purpose, input, and output format. It is complete enough for an agent to use correctly, though it could briefly mention error handling for a fully comprehensive picture.

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 describes the 'url' parameter, but the description adds that the URL must be 'as returned by search_lessons or get_track', clarifying its provenance and format. This extra context goes beyond the schema's basic field description.

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 action ('Fetch the full text of a lesson') and the required input (URL from search_lessons or get_track). This distinguishes it from sibling tools that search or list tracks, making its purpose unambiguous.

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 implies a prerequisite: the URL must come from search_lessons or get_track. This gives clear context on how to obtain the URL, though it does not explicitly state when not to use the tool or mention alternatives for finding lessons.

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