fetchExistingVideoSummary

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

The description reveals no details about return values, error handling, or behavior when no summary exists. Without annotations (readOnlyHint, destructiveHint), the agent has no explicit indication that this is a safe read operation, though the word 'fetch' implies it. It also does not mention prerequisites like a valid videoId or database accessibility.

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 a single, front-loaded sentence that directly states the tool's action without unnecessary words. It earns a high score for conciseness and clarity.

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 one-parameter retrieval tool, the description gives the core purpose but omits outcome details such as whether a missing summary returns null or an error. Since there is no output schema, the agent must infer the return type, leaving some ambiguity in edge cases. This is adequate but not fully complete.

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 input schema fully documents the single parameter videoId as 'YouTube video ID', so the description need not elaborate. The description itself does not mention the parameter, but the schema covers it adequately; baseline of 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's function: fetching an existing summary from a database. It distinguishes from siblings (get transcript, search, store) by specifying 'existing video summary' and 'database', making its purpose unmistakable.

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 usage when a videoId is available and a previously stored summary is needed, but it does not explicitly reference alternative tools or state when not to use it. Sibling tools like get_youtube_transcript and storeVideoSummary are absent from the guidance, so the agent must infer usage context from the name alone.

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