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

Annotations already declare readOnlyHint=true, so the safety profile is covered and the bar is lower. The description adds the underlying REST endpoint (GET /opportunities/{id}), which is mildly useful, but it says nothing about not-found behavior, permissions, or return shape beyond the generic 'get'.

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?

Two short sentences, zero filler, with the core action front-loaded and the REST endpoint relegated to a supporting clause. Every sentence 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 one-parameter read-only lookup with full schema coverage and readOnlyHint, this is nearly sufficient. The only real gap is that no output schema exists, so the description could hint at what an opportunity record contains, but that omission is minor for a trivial getter.

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% and the single 'id' parameter is documented in the schema as 'The opportunity id.' The description adds only the words 'by id', which restates rather than enriches the schema. 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?

States a specific verb and resource ('Get a single opportunity (deal) by id'), with the 'single' + 'by id' framing implicitly distinguishing it from the sibling copper_search_opportunities / copper_list_pipelines style list tools. It does not name that alternative outright, so it falls just short of full sibling differentiation.

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?

Usage is only implied: the 'by id' phrasing signals you must already hold an opportunity id, which rules out the search/listing siblings. There is no explicit when-to-use statement, no guidance for what to do when the id is unknown (i.e. search first), and no exclusion notes.

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