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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds the mode-switching behavior (fetch vs list) and implies the output includes parts, but does not detail pagination, error handling, or auth, which is acceptable given the read-only nature and existing output schema.

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 zero fluff, front-loads the primary action, and efficiently covers both modes of operation. Every word earns its place.

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 optional parameter and an output schema, the description covers the essential behaviors and use case. It does not explain the return structure, but that is handled by the output schema. The dual-mode behavior is clearly communicated.

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 description for projectId is already descriptive and covers 100% of the parameter meaning. The tool description essentially repeats the same info, so it adds minimal new semantic value beyond what the schema provides. Baseline 3 applies.

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 uses the specific verb 'Fetch' with a clear resource 'Story project and its parts', and explicitly distinguishes the dual behavior (fetch by ID vs list recent projects). This clearly differentiates it from creation/generation tools like create_storyboard and generate_storyboard_part.

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?

It provides a direct use case: 'Use this to pick up a story and continue the next part.' This implies when to use it, but does not explicitly state when not to use it or mention alternatives, leaving that to inference from sibling names.

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