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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=false, so the safety profile is known. The description adds meaningful behavioral context: upsert semantics, partial-update behavior ('changing only the fields you send'), and creation requirements. It doesn't describe return values, but with no output schema and annotations covering the safety profile, the added context is valuable.

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 compact and front-loaded with the core upsert behavior, then moves to usage guidance. The list of project types is slightly long but earns its place by helping the agent identify what to save. No redundant restatement of the schema.

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 13-parameter tool with no output schema, the description covers the key decision (create vs update), prerequisites (get_profile), and content guidance. It doesn't explain what happens after saving (e.g., confirmation, return value), but the absence of an output schema and the presence of rich parameter descriptions make this acceptable. The guidance about avoiding duplicates and not fabricating content is particularly valuable for an agent.

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 documents all 13 parameters. The description adds semantic value by explaining the id parameter's dual role (create vs update) and the required fields for creation, which is not fully captured in the schema's per-parameter descriptions. It also adds guidance on what kinds of projects to include, which helps the agent populate fields meaningfully.

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 opens with a specific verb and resource ('Add or update a portfolio project (upsert)') and immediately distinguishes the two modes (create vs update) with explicit field requirements. It also names the sibling tool get_profile as the source for the id, which differentiates it from other save_* siblings like save_education and save_work_experience.

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 gives explicit when-to-use guidance: 'Check get_profile first to avoid duplicates' and 'Help the user recognize work they might not think of' with concrete examples. It also states what not to do ('don't fabricate or embellish'). This is strong usage guidance beyond just a definition.

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