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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds valuable behavior beyond that: omitting repositoryId lists all repositories first, requires DEVOPS_ORG_URL + DEVOPS_PAT with Code: Read scope, and summarizes the return fields. This adds meaningful context without contradicting the annotations.

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 fairly long but front-loaded with the PRIORITY TRIGGER and exclusion warning, followed by the core function, filters, return values, and prerequisites. Every section earns its place, though the long trigger list could arguably be trimmed. Overall it is dense but structured and efficient.

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?

With no output schema, the description compensates by listing the returned fields (PR ID, title, author, branches, review status, work items, creation date). It also covers triggers, exclusions, behavior, filters, auth requirements, and related tools. For a read-only listing tool, everything an agent needs to select and invoke it correctly is present.

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%, giving a solid baseline of 3. The description adds value by summarizing the supported filters (status, author, target branch) and restating the repositoryId fallback behavior in natural language. This reinforces parameter meaning without duplicating every schema detail.

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 and resource: 'List Pull Requests in an Azure DevOps Git repository'. It clearly distinguishes itself from siblings by explicitly prohibiting search_d365_code for PR listing and by pointing to ado_analyze_pr_impact for impact analysis. An agent can immediately tell what this tool does and how it differs from similar tools.

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?

A PRIORITY TRIGGER block lists concrete user phrasings that should route to this tool, and the description explicitly says 'NEVER call search_d365_code for PR listing requests'. It also names ado_analyze_pr_impact as the follow-up tool for impact analysis, giving clear when-to-use and when-not-to-use guidance.

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